Summer 2021 Vol. 64 No. 3 by Association of Environmental & Engineering Geologists (AEG)

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Vol. 64, No. 3 – Summer 2021

INSIDE…

Professional Contributions:

PALEOSEISMOLOGY

Special Feature

AEG 2021 San Antonio

AEG 64th Annual Meeting

The Westin Riverwalk September 20–26, 2021

www.aegannualmeeting.org

Guest Tours

Hill Country Wine Tasting & Fredericksburg Shopping San Antonio Missions World Heritage Tour San Antonio Riverwalk Walking Tour Natural Bridge Caverns

Field Courses

The Westin Riverwalk

Situated on the Riverwalk’s quiet end, this upscale hotel is near the Pearl District, home to downtown restaurants, bars, shopping and entertainment. Walk to the historic Alamo or the Spanish Governor’s Palace to admire its white adobe architecture. Enjoy beautiful indoor and outdoor venues overlooking the Riverwalk. The hotel rooms and suites feature pillowtop mattresses, marble bathrooms and room service. As you revel in Riverwalk views from a private balcony, feel the energy of downtown San Antonio at The Westin.

Texas Hill Country Terroir Experience San Miguel Lignite Mine San Antonio River Improvements Project Karst Cave – Cave Without a Name San Antonio Water System H2Oaks Facility – Keeping San Antonio Drinking Canyon Lake Gorge

Technical Program

We are still accepting abstracts for SOME topics. Visit the Technical Program tab at www.aegannualmeeting.org for complete details.

SYMPOSIA TOPICS Dams and Levees Landslides Coastal Hazards Environmental: Topic 1,4 Dioxane Geologic and Seismic Hazards Geophysics GeoUAS (Drones) Tunneling Diversity Subsidence/Karst/Groundwater

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Vol. 64, No. 3 – Summer 2021

AEG News (ISSN 0899-5788; USPS 954-380) is published by the Association of Environmental & Engineering Geologists (AEG), 3053 Nationwide Pkwy., Brunswick, OH 44212, four times a year in April, July, and December with the Annual Report and Directory in March. The Annual Meeting Program with Abstracts is published only digitally, in September, and the digital copies are distributed at the AEG Annual Meeting. Association members receive an electronic copy of all five issues of the AEG News as part of their dues. Print subscription for Association members, which includes all three regular issues of the AEG News and the Annual Report and Directory issue, is $40 in addition to annual membership dues. Nonmember annual subscription is $50. Back copies of AEG News regular issues are $12 each. Inquiries should be sent to AEG Headquarters: Association Manager, 3053 Nationwide Parkway, Brunswick, OH 44212 330-578-4900.

Periodical Postage paid at Brunswick, OH, and additional mailing offices: POSTMASTER: Send address changes to AEG News, 3053 Nationwide Pkwy., Brunswick, OH 44212. © 2021 Association of Environmental & Engineering Geologists—All Rights Reserved Views expressed in this publication are not necessarily those officially representing the Association of Environmental & Engineering Geologists except where expressly stated.

AEG News Editors Acquisitions Editor: Martha Whitney, Principal Engineering Geologist, Whitney Geologic, news@aegweb.org Content Editor: Bill Roman, Chief Geologist, Gannett Fleming, Inc., wroman@gfnet.com Managing Editor/Production: Andrea Leigh Ptak, Communicating Words & Images, 206-300-2067, andrealeighptak@me.com, www.andrealeighptak.com

Submission Information In order of preference: 1. Send files via email, preferably as attachments, to both email addresses above. Optimum file format is MSWord. Users of other software programs should convert their file to ASCII or text only. Photos and other images, charts, graphs, etc.) should be sent as separate images but may be included in the Word.doc for placement purposes. 2. Images should be sent as high-resolution (250 dpi at 4” wide or larger) jpeg or tiff files and should be named with a strong identifier such as HF-Texas-John Jones —NOT P204679.jpg. Corresponding photo captions should be included in the text along with an attribution of the source/photographer. 3. The policy of AEG News editorial staff is to limit the credentials of an individual to two. No effort will be made by the AEG News editorial staff to determine if individuals whose credentials are missing from the submitted copy actually have academic or professional credentials, nor will the staff verify the existence or correctness of the credentials submitted. For detailed guidelines visit: https://aeg.memberclicks.net/assets/docs/aeg_news_style_guide_0713.pdf

Advertising in the News Contact AEG Headquarters at advertising@aegweb.org.

Table of Contents Index to Advertisers

From the Editors 4 Your Questions & Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 The Acquisition Editor’s Pen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 In This Issue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 News of the Association 6 The President’s Message . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 Vice President’s Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 Treasurer’s Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 Secretary’s Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 Headquarters’ Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 Foundation Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 Committee Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 Special Section – 2021 Annual Meeting Preview

Professional Contributions 22 50 Years of Paleoseismology: The Science and the Business . . . . . . . . .22 The Role of Paleoseismic Investigations in the Engineering of Pipeline Fault Crossings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26 iPad Lidar Scanning for 3D Trenching . . . . . . . . . . . . . . . . . . . . . . . . . .29 Paleoseismology in Wine Country . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34 The 1811–12 New Madrid Earthquakes – The Backstory . . . . . . . . . . . .42 The HomeFront

On the Cover A tour of The San Antonio River Improvements Project is just one of the Field Courses offered during our Annual Meeting in September. Learn about it and more in our Special Section beginning on page 12.

The association 2020–21 Officers President: WILLIAM GODWIN Consulting Geologist, Carmel, California, president@aegweb.org Vice President/President Elect: MADDIE GERMAN Atlantic Coast Consulting, Atlanta, Georgia, VP@aegweb.org Treasurer: NATHAN SARACENO Senior Geologist, DiGioia Gray and Associates, Monroeville, Pennsylvania, treasurer@aegweb.org Secretary: SARAH KALIKA Consulting Geologist, DiabloGeo Environmental, San Ramon, California, secretary@aegweb.org Past President: CYNTHIA PALOMARES Texas Engineering Extension Service, Texas A&M University, Caldwell, Texas, PP@aegweb.org

Association Contacts

Submission Deadlines https://www.aegweb.org/aeg-news-2 Canada Agreement number: PM40063731; Return Undeliverable Canadian Addresses to: Station A, PO Box 54; Windsor, ON N9A 6J5; Email: returnsil@imex.pb.com

Headquarters: Association Manager: SHERI MASKOW J&M Business Solutions 3053 Nationwide Parkway, Brunswick, OH 44212 330-578-4900, manager@aegweb.org AEG Foundation—President: KEN NEAL, president@aegfoundation.org Communications Co-Directors: BILL ROMAN, wroman@gfnet.com and ISAAC POPE, Pi2017earthscience@outlook.com

Summer 2021

AEG NEWS 64(3)

FROM THE EDITORS Advisory Committee or attend one of their meetings and bring up your ideas. https://aeg.memberclicks.net/operational-committees

Your

Questions &Answers

Q2) Why don’t all 50 States have professional geologic licensure?

Get answers and information from AEG members on your industry and associationrelated questions.

In each issue, questions sent by any member will be posted along with the response from the official to whom it is addressed. If the questions are general in nature, then the AEG News editorial staff will research it and post the response, otherwise a specific AEG official will respond to the question. Please send your questions, comments, input, or suggestions to Martha Whitney, AEG News Acquisitions Editor at news@aegweb.org. This issue’s questions answered by AEG President Bill Godwin…

Currently 34 states or territories (Puerto Rico) have requirements for professional licensure in geology. The National Association of State Boards of Geology (ASBOG®) serves as a connective link among the individual state geologic registration licensing boards for the planning and preparation of uniform procedures (tests). The other 17 states are considered Nonregulatory States. Other organizations such as the American Institute of Professional Geologists (AIPG) certify professional geologists based on their competence, integrity, and ethics through a peer review process. Professional boards and the state governments behind them determine whether licensure is required to practice in their state. AEG supports licensure in all 50 states and can provide the means to prepare a licensure act. https://aeg.memberclicks.net/licensure-resources

Q3) What are the three most common geology questions you receive and what is your reply? 1) When is the next big earthquake? We can’t yet determine that, but it will come soon! 2) Did you find gold (asked when logging on a drill rig)? No, but if I do, you’ll be the first to know.

Q1) How can I organize an AEG field trip or professional forum in my area? There are several ways to do this. AEG has technical working groups or TWGs that focus on such topics as Coastal Hazards, Tunneling, Hydrogeology, Environmental Characterization and Remediation. These TWGs generally have seasoned experts who not only know about the subject but also have organized these types of events. Another way is to gather enthusiasm via a Chapter if the event you want is of local interest. Typically, these events can generate revenue for Chapters. Lastly there are means by which joint meetings with other organizations such as the National Groundwater Association or Geotechnical Institute can be organized. Contact members of the Meetings

3) Can you tell me what type of rock this is? Sure, but it’s important to get it wet and look at it under good light. Oh, I’m sorry I forgot my hand lens (when I don’t know).

o t x e d In vertisers Ad

AEG Corporate Sponsor Listing . . . . . . . . . . . . .8 University of Arizona . . . . . . . . .Inside Back Cover UPenn . . . . . . . . . . . . . . . . . . . . . . . .Back Cover AEG 2021 Annual Meeting . . . .Inside Front Cover AEG 2021 Annual Meeting Sponsor Opportunities . . . . . . . . . . . . . . . . . . .25 AEG Future Meetings . . . . . . . . . . . . . . . . . . .33 To advertise in AEG News, contact AEG Headquarters at advertising@aegweb.org

Historic missions are just some of the attractions to be found in San Antonio, the site of the 2021 AEG Annual Meeting. Meeting details can be found in our Special Section beginning on page 12. AEG NEWS 64(3)

Summer 2021

HERE FROMHEADER THE EDITORS

Acquisition Editor’s Pen Martha Whitney, AEG News Acquisitions Editor

elcome to the Summer Edition of AEG News. This is an exciting time as we cautiously emerge from our various degrees of isolation. I am grateful to be fully vaccinated and able to visit family and friends in the United States and I am looking forward to meeting new friends (in person!) at the Annual Meeting in San Antonio in September. In addition to details on the Annual Meeting, this issue includes five technical contributions from some of the leading experts in the field of paleoseismology. James McCalpin and Eldon Gath bring us a synopsis of 50 years of Paleoseismology; we have an update on the Rodgers Creek Fault in California from the team at Lettis Consultants International; Ian Pierce and Rich Koehler present a new methodology using the laser scanner of an iPad Pro to provide reference and accurately scale Structure from Motion models of deformation in the northern Walker Lane; Hengesh et al., present an argument for enhanced risk assessments through validation trenching of pipeline fault crossings; and Phyllis Steckel tells the story of the New Madrid Seismic Zone that is not only a fascinating geo-social summary of the historic events from a geo-political perspective, but also a call to action. We hope you enjoy these technical contributions and that perhaps they inspire you to attend the Annual Meeting. Many of the authors will be presenting at the special symposia hosted by the Geologic and Seismic Hazards (GASH) Technical Working

Group (TWG): Evaluating Geologic and Seismic Hazards and the Potential Need for Hazard Mitigation. Speaking of Technical Working Groups, did you know that there are 15 TWGs and 16 Operational Committees within our organisation? From Diversity, Equity and Inclusion, K–12 Education, and Licensure Committees on the operational side to Rock Mechanics, Environmental Characterisation and Remediation, GASH, and Tunnelling on the technical side, a plethora of opportunities exist to network, learn, and advocate for academic, professional, technical, and social initiatives. In addition, there are 26 Local Chapters covering 11 Regions: ten within the United States and one to serve our international members. Discover the many ways AEG can enhance your professional (and personal) life. Visit https://aeg.memberclicks.net/volunteer-main and https://aeg.memberclicks.net/regions-chapters to learn more. Finally, AEG News welcomes, and indeed, encourages contributions from all our members. If you attend a Local Chapter field trip or meeting, send in a photo and perhaps a synopsis of the event. For those of you planning to attend the Annual Meeting in San Antonio, and particularly any of the field courses, consider writing an article, with a photograph or two, that we can publish in the Winter Edition of AEG News. News of the profession, memorials, member publications are also welcome. Please send submissions to news@aegweb.org.

In this issue…

Bill Roman, Content Editor

he editors welcome you to the Summer issue of AEG News, which further eases us back to our pre-Covid lifestyle by previewing AEG’s 2021 Annual Meeting—our first non-virtual Annual Meeting since 2019. In the News of the Association, AEG’s President Bill Godwin reflects on the past year, looks forward to the Annual Meeting, and encourages us to invite our colleagues to join AEG; Vice President Maddie German discusses the role AEG can play in developing our leadership skills; Treasurer Nate Saraceno provides an update on AEG's finances; and Secretary Sarah Kalika announces AEG will be using new software to improve efficiency and discusses the use of pronoun preference badge stickers at the Annual Meeting.

In other news, we are pleased to include an update from the AEG Foundation; a report from Deborah Green on what AEG is doing to support diversity, equity, and inclusion in the geosciences; Bruce Rogers’ report on the exciting things happening in the Nashville Chapter; and President Bill Godwin’s responses to your questions in our Q&A section. In our professional contributions section, Acquisitions Editor Martha Whitney has assembled an outstanding collection of essays focusing on paleoseismology. So, we hope this issue of AEG News enhances your summer reading, and we look forward to your contributions to our next issue.

HELP WANTED AT THE ANNUAL MEETING: Aspiring PHOTOGRAPHERS attending AEG's 2021 Annual Meeting are urged to submit their best shots of field trips, guest tours, technical sessions, social gatherings, and people just having fun. See page 3 for photo requirements. We also welcome reports on the various field trips and other events for possible publication in the meeting summary in the Winter issue of AEG News. Submit to to news@aegweb.org.

Summer 2021

AEG NEWS 64(3)

NEWS OFHERE THE ASSOCIATION – THE PRESIDENT’S MESSAGE HEADER

About to Turn A Corner William Godwin, 2020 –21 AEG President

rior to preparing articles for the AEG News, I usually look back to previous issues to see what was current at the time. I call this Georecall. While this is not a complete remedy for writer’s block, it does afford me the opportunity to see how AEG topics and issues have progressed over the past few years. Needless to say, COVID-19 has dominated our activities the last year and a half. In last years’ Summer issue, then President Cynthia Palomares reported that she had to cancel a number of Chapter visits due to COVID. This year as President, I have had to “visit” several Chapters via webinars, yet by late this Summer, I hope to make real visits to the three Chapters in the Pacific Northwest and possibly a couple back in the eastern US. I am really looking forward to that and would encourage you to reach out if you would like me to visit your Chapter. Cynthia also reported the implementation of our national webinar series. I am happy to report that we have held 27 webinars (two by me) since April of 2020. We plan to continue having one or two per month on a variety of topics. If you have an idea for a webinar or know someone else who does, please contact me. Our upcoming Annual Meeting, planned for September 20–24 in San Antonio, Texas, is going to happen as a face-toface meeting. Recall that last year we had to switch to a virtual format due to COVID. This year’s meeting should be a lot of fun and allow us to meet one another again, attend field trips, and other social functions. This issue of AEG News provides all the

information you will need to safely attend and participate in AEG’s biggest function of the year. I ask that we all follow the protocols outlined in the meeting program when it comes to the venue rules. A reflection on our membership for 2021 (see Nate Saraceno’s Treasurer’s report) shows that our membership numbers have actually gone up. This is so encouraging to me and the Executive Council (EC). We were very concerned that membership would dip during the pandemic since members were not allowed to meet in person, and generally trend downward, which has happened with other professional organizations. This good news is really the result of hard work by our Chapters, better functionality of our Memberclicks website platform, and connectivity via Social Media on the happenings with AEG. All this is supported by the desire of geologists to stay connected. As things open up this Summer, please make the effort to invite someone to our Chapter meetings, field trips, or short courses. Introduce them to other AEG members, stay connected and allow them to make a decision to join AEG. I thank many old-timers who did the same for me in the San Francisco Bay area back in the 1980s and 1990s. I would like to extend heartfelt thanks to all the volunteers who spend time and effort to make AEG what it is, a touchstone and voice for practicing geologists. I look forward to seeing you all in San Antonio in September. If you have any questions or concerns, please reach out to me at president@aegweb.org.

In Recognition…

Call for Volunteers! Technical Working Groups

Stuart Hoffman William Godwin, President of AEG, is recognizing Stuart Hoffman, owner of Star Publishing with a Lifetime Contribution Towards Publishing Excellence Award. Over the years Star Publishing has supported AEG and the geology profession with classic publications such as the Geology of the Cities of the World Series, Engineering Geology Practice in Southern California, Environmental, Groundwater and Engineering Geology, Applications from Oregon, and more recently Applied Geology in California. Publications are a key benefit to membership in AEG and Stuart has been instrumental in providing top notch reference materials. Founded in 1978, Star has published college/university textbooks, laboratory manuals, specialized reference books for laboratory medicine and clinicians, several engineering and environmental geology books in co-ordination with AEG, and local history books related to California.

Are you an expert in or have an interest in a specific technical issue? AEG TWGs are in place to pursue a technical task or engineering/scientific issue, which is of importance to the membership and in accordance with our objectives. Major goals of TWGs are to monitor new developments in the special technical fields, bringing them to the attention of our membership through timely articles in AEG News and our website; to cooperate with other professional/technical societies and organizations in organizing and presenting seminars and conferences on the TWG’s technical specialty; and, to formulate draft policy statements and position papers for Board consideration in a professional and timely manner. The following list of Technical Areas of Focus includes the primary practice specialties of our members: Dams & Levees • Environmental Characterization & Remediation • Coastal Hazards • Geophysics • Hydrogeology (co-chair needed) • Landslides • Naturally Occurring Asbestos • Rock Mechanics • Geologic and Seismic Hazards • Solid, Hazardous & Mine Waste Management • Subsidence • Tunneling If you are interested in volunteering for a group, please contact Cynthia Palomares at pp@aegweb.org.

AEG NEWS 64(3)

Summer 2021

NEWS OF THE ASSOCIATION – VICE PRESIDENT’S HEADER REPORT HERE

Looking for Leaders Maddie German, 2020 –21 AEG Vice President

s the leader the most imposing figure or the loudest voice in the room? Not always, however, it is probable a leader will be involved in thoughtful listening while participating in humble and honest communication. While good leaders possess personal opinions, these don’t drive their agenda. These folks appreciate and respect everyone in their business from the most entry level individual to the president and CEO. They work and inspire others to support the team’s mission. Look around… look in the mirror…do you see this person? Gaining leadership skills doesn’t happen overnight. Rather they are developed over time with continual focus and energy on cultivating this skill set. One way to develop these essential skills (for AEG, business and life) is by starting small and allowing yourself to accept gradually larger Let AEG responsibilities. involvement Not all leadership positions are foster that public facing roles (thank goodness) because not everyone leadership aspires to lead their local PTA or skill set become President of the United in you. States. You can be a leader within your office, helping keep your team on track and task, or by working behind the scenes in your local AEG Chapter, or organizing a meeting. AEG has many opportunities for members, in various stages of their careers, to bolster their leadership skills.

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Here are some suggestions where anyone can start, right now: ■ joining or co-chairing one of AEGs many Committees or Technical Working Groups; ■ signing up to track geological related legislation in your state; ■ volunteering as an officer for your local Chapter; or ■ running for the Regional Director position in your Region. Of course, AEG has fantastic volunteers who have been working within the organization for many years (extensive gratitude goes out to these dedicated individuals), still, there is always room for more amazing people to join their ranks! Each new person brings new ideas and energy that continually make AEG better. AEG makes space available to develop new leaders and provides the opportunity for anyone to step up and help. Let AEG involvement foster that leadership skill set in you. Great leaders are curated over time; start the process for yourself. As more amazing members volunteer, our combined energies build a stronger organization and allow our efforts to be more effective. You can make this commitment to become better for yourself, for your life, for your family, for your future and the future of AEG. Step away from the mirror, and instead, let your reflection be projected back from AEGs evolving story. Help us give the opportunity to build a more valuable career and personal skillset to yourself and the rest of our membership. We look forward to working with you!

Leadership Opportunities Immediately Available! Bolster Your Resume

Interested?

Practice leadership skills with your fellow geoscientists from across the US and the globe. Share ideas and manage projects while working to support AEG and promote the Geosciences.

Contact the committee co-chairs listed on the website or AEG VP Maddie German at vp@aegweb.org to become involved or get more information.

IMMEDIATE COMMITTEE NEEDS: Build Friendships Working together for a common purpose you will build community and form relationships with like-minded individuals. The added bonus is always connecting in-person at the annual meeting.

Choose Your Time Commitment Operational committees typically meet once per month for one hour. (That is only 12 hours per year). You can commit to as many activities as your schedule allows.

Summer 2021

K–12 Committee – Enjoy working with students, planning science fairs, and sharing the wonders of the Earth (and beyond) with future generations? This committee is for you! Student & Young Professional Support Committee – A meeting place for college and university students as well as those entering the workforce in their first few years after graduating, to share skills, tips, advice, and stories. Also, for those seeking to help young geologists on their journey with practical advice and knowledge.

AEG NEWS 64(3)

HEADER NEWS OFHERE THE ASSOCIATION – TREASURER’S REPORT

Looking Ahead to Build Our Future Nathan Saraceno, 2020 –21 AEG Treasurer AEG’s fiscal assets consist of monies held in three bank accounts and a separate investment account for Operations, Annual Meeting, and Licensure funds, as well as a Fidelity investment account for the Treasurer’s Reserve. As of April 30, 2021, our total fiscal assets are at $1,159,932, and the Treasurer’s Reserve balance is $456,920.

Annual Meeting The upcoming 2021 Annual Meeting will take place in person in San Antonio! We continue to closely monitor the situation as it pertains to the ongoing pandemic, but the outlook is positive. In order to keep safety a number one priority, will be requiring all attendees abide by the CDC and conference center hotel’s COVID guidelines, current at the time of the meeting. In addition to our Special Section beginning on page 12 in this issue, you can read more about the great technical program and exciting field trips we have in store via the Annual Meeting website: www.aegannualmeeting.org.

Corporartse 2021 Sponso Kilimanjaro

The 2021 Annual Meeting revenue so far this year is on track and totals $52,270 through April 30, 2021, compared with the annual budget of $248,740. Revenue includes registration fees and special event, exhibits, and sponsorship income. As of June 2, full meeting registrants are at 32 attendees. To break even, 155 attendees are needed. We expect at least 200 attendees to register as a majority of meeting registrations generally occur during the month before the Annual Meeting. Therefore, we anticipate to at least meet our budgeted surplus of $28,315. Sponsorships as of June 2 are at $31,090 compared to the budget of $25,000. This is encouraging and may signify general eagerness for attending the in-person meeting.

Membership Update Membership revenue for 2021 is $161,594 as of April 30, 2021, compared with the annual budget of $184,225. Total membership is at 1,702 as of April (not counting 708 students), compared to 1,475 this same time last year. Let’s keep this momentum going!

Kilauea Collier Geophysics, LLC Phil Sirles, 7711 W 6th Ave., Suite G Lakewood, CO 80214 720-487-9200 https://colliergeophysics.com/

The University of Arizona College of Engineering (888) 658-2042 1209 East 2nd St., Room 100 Tucson, AZ 85721 onlineengineering@arizona.edu https://online.engineering.arizona.edu/online-eng-mining/

Lettis Consultants International, Inc. Earth Science Consultants Ion Bazgan, 1981 N. Broadway, Suite 330 Walnut Creek, CA 94596 (925) 482-0360 http://www.lettisci.com/

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AEG NEWS 64(3)

Summer 2021

NEWS OF THE ASSOCIATION – SECRETARY’S HEADER REPORT HERE

Changes, Improvements, & Innovations Sarah Kalika (she/her), 2020–21 AEG Secretary

s we get back to some level of “normal” this Summer, AEG leadership has been busy! We held online Executive Council (EC) meetings in January and April and an online Board of Directors (BOD) meeting in April. The EC is planning to meet in person for the first time in nearly two years at the Summer EC meeting, held at AEG’s Headquarters office in Ohio. We’re also planning to hold in-person meetings of the EC and BOD during the Annual Meeting in San Antonio.

reflected within an Amendment and added to the Bylaws, which AEG members can access via AEG's website under the Member Resources page.

Pronoun Badges at AEG’s Annual Meeting in San Antonio, Texas

Membership Workshop During the April BOD meeting, we held a collaborative workshop discussing AEG’s membership categories, ways to improve recognition of long-time members, and membership recruitment. As Secretary, I have convened a short-term task force to further explore membership and propose improvements to be implemented as soon as the next membership renewal cycle. Let me know if you’re interested in participating!

A Method to Improve Our Efficiency Following months of research by AEG’s Association Managers, the EC and BOD are starting to use BoardEffect—a software solution that houses meeting invitations, board documents, and facilitates casual communication (similar to Teams and Slack, if you’re familiar with those) by providing the ability to record quick responses instead of “replying all” within an email. This will cut down on the number of emails that members receive, particularly if they’re part of several committees. BoardEffect allows you to customize notification frequencies and export calendar appointments to most of the commonly used calendaring software systems, so you’ll never miss a meeting. Discussion subjects are threaded so committee member comments can be organized, and communication streamlined. With this system, the BOD can vote, submit, and review documents in advance of a meeting, and communicate with each other between meetings. This system also centralizes file storage and eliminates the need for committee members to store files on their personal computers, in DropBox, or Google Docs, or other file storage platforms that get lost or out of date over time. BoardEffect use will be rolled out to AEG’s Operational Committees over the next few months, and we hope this will lead to more efficient leadership of AEG. If you’re worried about learning another “new thing,” Association Manager Sheri Maskow reported that her favorite feature within BoardEffect is unlimited free training sessions!

Minor Bylaw Change The BOD voted in May to approve a minor change to AEG’s Bylaws, which updates AEG’s Association address to our current headquarters in Brunswick, Ohio. This change was Summer 2021

We’re looking forward to holding our Annual Meeting in-person this September and during this meeting you will notice a new feature—pronoun badge stickers! Why are pronouns important? Often, people make assumptions about a person’s gender based on how they look. Sometimes this assumption is not accurate and leads to confusion or embarrassment. Choosing to ignore a preferred pronoun can lead to a potentially harmful environment where members, colleagues, and friends feel like they’re not included or wanted within the geoscience profession. Similar to pronouncing someone’s name correctly, using a preferred pronoun helps foster an environment of respect, and it’s the right thing to do. You might have noticed that I included my preferred pronouns in my byline. At this year’s Annual Meeting, you will be asked to choose a green sticker to self-identify your pronouns. Participation is optional, but when we all identify our pronouns, it eliminates confusion and avoids guesswork! Some examples of pronouns include: she/hers, he/his, they/them, ze/hir, ze/zim, or no pronouns (use a person’s name instead). You can refer to people this way “Becks is giving a presentation this morning, let’s go support them!” or “Zara published a great article, you should ask Zara to tell you about Zara’s work.” It’s okay to ask about a preferred pronoun. What happens if you make a mistake and misgender someone? Don’t worry; but do correct yourself. An example of how to phrase this is, “Is that Mikal? I have been looking forward to seeing him—I mean, her! I read her abstract in the program and her paper looks fascinating.” No need to draw attention to your mistake, just correct your words to reflect Mikal’s pronouns. How do you share your own pronouns? We’ve made it easier by asking everyone to identify their own pronouns using the green sticker. What if you’re not sure, or someone has taken their name badge off? Again, don’t worry! A tactful way to ask is by introducing yourself and normalizing the concept of pronoun identification “Hi, my name is Sam, I go by she.” Are you someone who has never thought about pronouns? If so, you might be privileged that your appearance and name fit both your gender and the pronoun that many people associate with your gender or name, but this is not the case for everyone. Let’s normalize the use of pronouns so we all can feel included. To read more about pronouns, visit https://www.mypronouns.org. See you in September!

AEG NEWS 64(3)

NEWS OF THE ASSOCIATION – HEADQUARTERS’ REPORT

Getting Social

Sheri Maskow, Association Manager EG’s presence on social media is continuing to grow, now boasting the following audience numbers:

Instagram – 253 followers Twitter – 303 followers LinkedIn – 13,991 group members Facebook – 4,830 page likes & 321 group members

Additionally, we are working with Sarah Kalika to get the YouTube channel back up and running. The Student & Young

Professional Committee will be taking the lead on this initiative and will be discussing how to move forward with collecting content at their upcoming meetings. Look for more details in the coming months! Another exciting new announcement is the implementation of a program called BoardEffect, a board portal software that is easy to use and secure. A board portal is a type of secure, paperless software, or app, that allows you to communicate with board members, share documents, annotate meeting minutes, and more without any of the risks or waste that a paper board book provides. This will aid in managing board materials—including meeting scheduling, collaborations, and reporting. The software offers unlimited storage and has a strong platform for mobile use.

NEWS OF THE ASSOCIATION – FOUNDATION REPORT

Foundation Happenings at the Annual Meeting and More Nichole Wendlandt Vetter

Annual Meeting Events

3) Sponsor the AEGF’s Donor Reception at the Annual Meeting to help offset the cost incurred to host the event.

The AEG Foundation (AEGF) Board of Directors is pleased that we finally can have a face-to-face meeting in September at the Annual Meeting in San Antonio. We are looking forward to honoring our scholarship recipients and thanking our donors in person, as well as reestablishing old relationships.

Proceeds from these events will benefit the Foundation’s Floyd T. Johnston Operations Fund, which directly supports the Foundation’s operating expenses. Donations can be made online at https://www.aegfoundation.org/annual-meeting/.

Funding Opportunities 1) As usual, the Foundation will be holding a Silent Auction during the Annual Meeting. Browsing the auction offerings is an enjoyable pastime during breaks, for meeting attendees and their guests. We encourage our members to donate not only geology-related items but also artwork, collectibles, jewelry, even gourmet baskets of food, wine and beer. 2) AEG is hosting Field Course 1: Texas Hill Country Terroir Experience to benefit the Foundation (see page 14 for full details on this event). Additionally, individuals who donate between $500 and $999 in support of this wine-focused field trip receive one complimentary ticket for the field trip; donations of $1,000 or more receive two complimentary tickets.

Charity Compliance The AEG Foundation has always been registered as a charity in California where it is incorporated as required by California law. Recognizing that current AEG members reside in all but two of the states that require charities to register and knowing that the Foundation’s donation solicitation program reaches every state, the Foundation’s Board of Directors wanted to ensure that it was legally authorized to solicit donations nationwide. The AEG Foundation Board has contracted with Charity Compliance Solutions, Inc. to prepare and submit all required documents and fees to register the AEGF in every state. They will also track state charity registration programs and legislative changes in these programs. As with other AEGF operating expenses, this cost will be budgeted from the Floyd T. Johnston Operations Fund.

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NEWS OF THE ASSOCIATION – COMMITTEE REPORT

Diversity, Equity, and Inclusion Committee Deborah Green, Co-chair

Diversity, Equity, and Inclusion—What is AEG Doing? It is no secret that the geosciences are among the least diverse of the STEM fields, and the leadership of AEG recognizes its responsibility as a professional organization to address this important issue. Accordingly, in July 2020 the AEG Executive Council issued the following statement and placed it prominently on our website’s home page.

AEG supports diversity, equity, and inclusion in the Geosciences profession and in our organization. AEG leadership plans to further our efforts in promoting these values by challenging ourselves on what we can do better to encourage underrepresented populations to consider and obtain careers in the Geosciences and to foster a welcoming and inclusive environment within our Association and the Geosciences profession. In addition, AEG’s Executive Council has joined other geoscience societies, like GSA and AGU, in signing a statement prepared last December by the American Geosciences Institute (AGI), which you can read at: http://bit.ly/AGIDiversity.

Pursuant to the statement’s objectives, during its 2021 Annual Meeting in San Antonio, AEG will hold a symposium on diversity, equity and inclusion issues in the geosciences, which will feature several invited speakers and a panel discussion. In September 2020, AEG formed the Diversity, Equity, and Inclusion Committee (DEIC) as a standing, operational committee in the AEG structure. The committee is charged with coordinating efforts to increase diversity, equity, and inclusion in the Association, and in the environmental and engineering geology profession. One of its roles is to support Chapters in this work. Some Chapters are already active, while others have yet to identify this issue as a focus. Regardless of where your own chapter is on diversity, the DEIC is here to help by serving as a place to share ideas and experiences, and to provide speakers and resources for addressing diversity issues in our profession. The DEIC members are volunteers from across the spectrum of AEG’s membership who want to make a difference on diversity. We hope other committees, technical working groups, and chapters will consider finding coordinators to work with us on this timely and important issue. Deborah Green and Jennifer Bauer are co-chairing the DEIC and can be reached at DEIC@aegweb.org. Resolving issues of diversity, equity, and inclusion in the geosciences will require time, work, and patience. Injustices that have persisted for centuries will not be erased in a few short years. For every successful initiative, there may be others that lead to dead ends. What matters is our commitment and support for one another as we embark on this path, and the DEIC is here to provide structure and resources for that journey. We are working to educate ourselves on the bigger picture, while also beginning to plan (and, hopefully in 2021, to implement) achievable projects that will result in small, but meaningful, steps forward. Please let us know how we can help with your steps forward.

Get ready to experience the culture, history, and geology of San Antonio, Texas… …all while connecting with your AEG community during it’s in-person Annual Meeting. We’re thrilled to be offering a full in-person meeting again after our one-year hiatus due to covid restrictions. A preview of the offerings can be found on the following pages of this issue of AEG News… PHOTO: WWW.FLICKR.COM/PHOTOS/JDTORNOW/1346724309

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n o i t c e S l a i Spec Preview

AEG 64th Annual Meeting Rock-n the River

PHOTO BY VIKI BEDA/FLICKR CREATIVE COMMONS

San Antonio, Texas – September 20–26, 2021

Geology of San Antonio The City of San Antonio’s story begins between 65 and 145 million years ago when a vast inland sea covered the western interior of what is now North America. During this time, marine sequences consisting of limestones and clays were deposited. As the Cretaceous Period drew to a close, the extensive continental sea began to retreat toward the Gulf Basin. During this time, South Central Texas was receiving sediments from the eroding Rocky Mountains and thousands of feet of sediment accumulated. During the Miocene, the weight of these sediments created tension and caused faulting to occur. The Balcones Fault Zone was created as a result of this tension, leaving San Antonio on a “hinge” between the flat lying Edwards Plateau and the gently sloping Gulf Coastal Plain.

History of San Antonio The area we now know as San Antonio was called "Yanaguana" (Land of Spirit Waters) by the Native Americans who lived there for millennia. Spanish explorers first visited the area in 1691 and established the Mission San Antonio de Valero (later called the Alamo) in 1718. Spanish settlers were drawn to the area by 12

the abundance of fresh water springs. They built Catholic missions and an extensive system of irrigation ditches called acequias. These acequias diverted water from the San Antonio River to the missions and accompanying fields. San Antonio grew to be the second largest Spanish settlement in Texas. In 1836, Texas won its independence from Mexico—just a few months after the battle of the Alamo—and was annexed into the United States in 1845. All this time, the city of San Antonio continued to thrive and has grown into the city we see today.

Your Stay in San Antonio Once a frontier settlement in the Wild West, San Antonio’s unique culture stemming from its Native American roots and influx of Spanish, German, and Mexican immigrants and migrants from the American South, offers an abundance of history, arts, and exciting cuisine. The city is famous for its scenic River Walk, which makes getting around downtown a breeze. Stretching more than 24 kilometers from start to finish, the River Walk’s shaded pathways connect hundreds of shops, restaurants, hotels, historic landmarks, museums, and attractions. Take the River Walk to the north and you’ll find museums—filled with everything from Picassos to Western memorabilia—and the Pearl—an

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AEG2021 – ANNUAL MEETING PREVIEW exciting culinary and shopping destination. To the south, the River Walk leads to four Spanish missions that once provided shelter for frontier settlers and still provide some of the best bird watching spots around. Perhaps most notable of all San Antonio’s missions is the Alamo in the heart of downtown. The Westin Riverwalk, located on the Riverwalk’s quiet end, is a beautiful upscale hotel decorated to emphasize the historic Texas surroundings while providing a warm and subtle Spanish Colonial look and feel. Don’t miss this opportunity to be adventurous and inspired in this amazing city rich in history and culture!

Pearl District, home to downtown restaurants, bars, shopping and entertainment. Walk to the historic Alamo or the Spanish Governor’s Palace to admire its white adobe architecture. On the weekend, Six Flags Fiesta Texas and the San Antonio Zoo are just a short drive away. After an eventful day take a swim in our outdoor heated pool near our 24-hour WestinWORKOUT® Fitness Studio. Our hotel rooms and suites feature pillow-top mattresses, marble bathrooms, and room service. As you revel in River Walk views from a private balcony, feel the energy of downtown San Antonio at The Westin.

San Antonio Culture—A Dynamic Confluence

Group Rate: $199/night

At its core, the city is dynamic. The roots run deep, the heritage is rich and the confluence of cultures is celebrated. The population and cultural influences are diverse—Native American, Mexican, Tejano, German, Irish, Czechoslovakian, and more—and the appreciation of that diversity makes San Antonio shine. They ¡Viva! for Fiesta, wear silver and black for their Spurs, and beam with pride in their distinction of Military City USA®. Really, they can turn any occasion into a celebration. Come discover what’s old and explore what’s new in this diverse community, its offerings and celebrations! Visit https://www.visitsanantonio.com to discover even more…

(Group rate only available until 8/17/21)

Climate/What to Wear The average daytime high temperature is 90 degrees and nighttime low is 69 degrees. Bring season-appropriate clothing and a light jacket or sweater for the cooler evenings. The meeting attire is business casual. The only event that is more formal is the Annual Banquet where formal or semi-formal attire is suggested but not mandatory.

Annual Meeting Hotel Westin Riverwalk (210) 224-6500 Thrive during your stay at The Westin Riverwalk, San Antonio. Situated on the River Walk’s quiet end, our upscale hotel is near the

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AEG2021 – ANNUAL MEETING PREVIEW

Pre- & Post-Meeting Field Courses Field Course Disclaimer: Field courses will be filled on a first-come, first-served basis, and registration will be limited to the number of spaces shown. The indicated minimum and maximum numbers of participants are based on a combination of factors, including transportation, accessibility, and safety at roadside outcrops. Field courses are subject to cancellation if the minimum number of registrants is not met. Field course logistics (e.g., schedule, duration, route, transportation, location/number of stops, etc.) are also subject to change. Participants should be prepared for variable weather conditions and hiking on uneven ground. Field courses will proceed rain or shine. Additional information regarding the logistics of each field course will be provided to the paid registrants by the field course leader(s) at a later date, but well in advance of the course.

Field Course 1 Texas Hill Country Terroir Experience Date:

Monday, Sept. 20

Field Course 2 San Miguel Lignite Mine – San Miguel Electric Cooperative, Inc.

Time:

8:00am–6:00pm

Date:

Tuesday, Sept. 21

Time:

8:00am–5:00pm

Location: Departs from the Hotel Lobby Fee:

$170.00 before 8/1/21, $200.00 after 8/1/21 (Includes: Transportation, box lunch and wine tasting)

Leaders: Bill Flanigan, WDF Geosciences, LLC; Darrel Schmitz, Schmitz Geological Services, LLC; and Claire Babineaux, Northern Gulf Institute

Location: Departs from the Hotel Lobby Fee:

$70.00 before 8/1/21, $95.00 after 8/1/21 (Includes: Transportation, box lunch and guided tour)

Leaders: Nellie Frisbee (Permit Specialist), Joe Harris (Reclamation Supervisor), and Marilyn Czimer Long, PG

PHOTO COURTESY OF TEXASHILLCOUNTRY.COM

The San Miguel Lignite Mine is located about 1.5 hours south of San Antonio. On this field trip we will visit the mine and the adjoining power plant, owned by the San Miguel Electric Cooperative, Inc. We will meet the mine representatives at the main office for an orientation regarding general facility information, safety, site geology, mining operations, and the power generation plant. From the office, we will visit geologic outcrop(s) and observe the mining operations. These include overburden removal (two draglines) and the mining of four (or more) lignite seams (Jackson Group, Manning Formation, Eocene). Approximately 3+ million tons/year of lignite is delivered to the adjacent power plant, where 391 net megawatts of electricity are produced and supplied to nine member cooperatives across 42 South Texas counties. According to Forbes, prior to the pandemic Texas was fourth among the states with the most wine-making facilities with eight American Viticultural Areas (AVAs) and with the Hill Country AVA being the most popular. This excursion will visit selected wineries of the Hill Country AVA in central Texas. The wineries visited will have soil derived from differing geologic deposits providing for a unique terroir tasting experience. A box lunch will be provided at LBJ State Park located on the Pedernales River adjacent to former President Lyndon B. Johnson’s Ranch. Our excursion will depart San Antonio through the Balconies fault zone into the scenic Texas Hill Country along the edge of the Edwards Plateau and into the Llano uplift traversing Lower Cretaceous, Paleozoic, and Precambrian age terrains. Along the way more details will be provided on the geology and history of the area. Join us for this unique experience and support the AEG Foundation in its effectiveness. Trip Sponsorship is available through the AEG Foundation at https://www.aegfoundation.org. 14

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AEG2021 – ANNUAL MEETING PREVIEW Following lunch (on-site), a visit to the power plant has been arranged. Requirements: Must have closed-foot shoes/boots (due to some folks traveling steel-toed boots will not be required). Must have long-sleeved shirts (no short sleeves or tank tops). Safety glasses (Bring your own safety glasses, if possible; the mine office has a limited number). Hard hats (local attendees may bring their own hard hats; the mine does have hardhats for visitors) Bring you own sample bags; we hope to have some outcrop/sample stops. Cameras are allowed.

Field Course 4 Karst Cave – Cave Without a Name Date:

Tuesday, Sept. 21

Time:

9:00am–4:00pm

Location: Departs from the Hotel Lobby Fee:

$95.00 before 8/1/21, $120.00 after 8/1/21 (Includes: Transportation, box lunch and cave tour)

Leader:

TBD

Field Course 3 San Antonio River Improvements Project Date:

Tuesday, Sept. 21

Time:

8:00am–4:00pm

Location: Departs from the Hotel Lobby Fee:

$90.00 before 8/1/21, $115.00 after 8/1/21 (Includes: Transportation and box lunch)

Leader:

Brian Mast (San Antonio River Authority)

The San Antonio River Improvements Project (SARIP) was a $384.1 million investment by the City of San Antonio, Bexar County, San Antonio River Authority, the US Army Corps of Engineers (USACE), and the San Antonio River Foundation in flood control, amenities, ecosystem restoration and recreational improvements along 13 miles of the San Antonio River from Hildebrand Avenue south to Loop 410 South. The River Authority served as project manager for all sections of the SARIP and as local sponsor with USACE specifically for the Mission Reach. The main goals of the SARIP were restoring the ecosystems around the river and linking together access to the cultural institutions of San Antonio with a linear park, extended barge access, and improvements to over 15 miles of trails. These enhancements to the river encourage economic development, connect the communities of San Antonio, and provide space for people to enjoy recreational activities such as cycling, jogging, wildlife viewing, and access to paddling the river.

Summer 2021

Built in 1939, the stairwell into the cave has 126 steps descending to approximately 90 feet below the surface. The cave maintains a constant temperature of 66 degrees all year round. Within the cave there are two main areas. The main set of chambers open to the public make up the show cave, extending just over a quarter of a mile. This part of the cave consists of six large, well-lit rooms full of speleothems including stalactites, stalagmites, helictites, columns, and draperies. The second main area of the cave is an extensive set of caverns linked to the underground extension of the Guadalupe River. During a 1975 expedition of the Cave Without A Name, cavers mapped out over 2.7 miles of caverns, making it the seventh longest cave in Texas. Some of the unique features of the cave include the 50-foot-long (15 m) set of rimstone dams beneath the natural spring-fed pool, the 19-foot-long (5.8 m) draperies referred to by the cave’s tour guides as “Texas-sized cave bacon,” and a collection of stalagmites that resemble the

AEG NEWS 64 (3)

AEG2021 – ANNUAL MEETING PREVIEW nativity scene. In the winter months, the cave becomes home for between five to ten dozen eastern pipistrelle bats. The seasonal inhabitants do not interfere with the tours as they use the cave only for hibernation. Another resident of the cave is a rare, blind Texas salamander known as the Kendall salamander that may be found only in the Cave Without A Name and another area cave, Cascade Caverns.

Field Course 5 San Antonio Water System H2Oaks Facility – Keeping San Antonio Drinking Date:

Saturday, Sept. 25

Time:

9:00am–3:00pm

Field Course 6 Canyon Lake Gorge Date:

Saturday, Sept. 25

Time:

8:00am–4:45pm

Location: Departs from the Hotel Lobby Fee:

$100.00 before 8/1/21, $125.00 after 8/1/21 (Includes: Transportation and a box lunch)

Leader:

Randy Mattzela, FPM Remediations, Inc.

Location: Departs from the Hotel Lobby Fee:

$70.00 before 8/1/21, $95.00 after 8/1/21 (Includes: Transportation and Box lunch)

Leader:

Joe Smith (San Antonio Water System)

San Antonio Water System (SAWS) serves 1.9 million people in Bexar County as well as parts of Medina and Atascosa counties. The population includes more than 511,300 water customers and 457,600 wastewater customers. The $192 million H2Oaks facility is one the largest inland water desalination plants in the United States. The state-of-the-art plant pumps brackish water from the Wilcox Aquifer and uses a system of reverse osmosis membranes to purify 12 million gallons of water per day, which is enough to supply 53,000 homes. The H2Oaks facility is also the home of SAWS Aquifer Storage and Recovery (ASR) facility. ASR technology is a proven method of storing water underground. The concept is simple. Water is pumped from the Edwards Aquifer throughout the year and stored in the Carrizo Aquifer in southern Bexar County. Later, during the hot, dry periods, the drinking water is pumped back into the existing distribution system to help meet demand. If water is not required to be recovered during the current year, it can remain in storage until required in a future year. As of December 2020, more than 173,527 acre-feet of water was stored underground.

This is a unique opportunity to study the geomorphological power of rapidly moving water and rapid canyon formation. Canyon Lake Gorge is a limestone gorge around one mile long, hundreds of yards wide, and up to 50 feet deep. The gorge was exposed in 2002 when 67,000 cubic feet (1,900 m3) of water per second flowed over the spillway of Canyon Lake, Texas for approximately six weeks, the first time the spillway had been in use since the reservoir dam was constructed in 1964. Normally, the flow out of the reservoir is around 350 cubic feet (9.9 m3) of water per second. The Guadalupe River basin forms a part of “Flash Flood Alley,” which is one of the river basins most prone to flash flooding in the world. Nine people were killed by the flood over a 20-mile (32 km) stretch of the river, which damaged or destroyed 48,000 homes and cost around $1 billion in damages, but the Canyon Lake manager has stated that even though the floodwaters went over the spillway, the dam still prevented an estimated $38.6 million in damages downstream during the event. The gorge provides a valuable exposure of rock strata as old as 111 million years showing fossils and a set of dinosaur tracks, and forms a new ecosystem for wildlife with carp and other creatures in a series of pools fed by springs and waterfalls. The Gorge Preservation Society formed as a local citizen’s group to develop long-term plans for the Gorge in partnership with the Guadalupe-Blanco River Authority and the US Army Corps of Engineers. No rock or fossil collecting is allowed. The guided hike and tour last about three to four hours. On this tour, expect to see the amazing power of water on the limestone formations in this area. Expect a few deer and if you are lucky, a UTSA mascot (beep beep) sighting during this eventful morning field trip.

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AEG2021 – ANNUAL MEETING PREVIEW

Guest Tours

Guests of attendees are a special part of the Annual Meeting. The local committee takes great care to help make their time at the meeting pleasant and entertaining by offering a variety of activities while attendees participate in the daily sessions. Guest Registrations are a great value and include the Opening Welcome Icebreaker and unlimited entrance to the Exhibit Hall with all day coffee. *Must have an Annual Meeting or Guest Registration to attend Guest Tours.

Guest Tour 1 San Antonio Missions World Heritage Tour Date:

Tuesday, Sept. 21

Guest Tour 2 Hill Country Wine Tasting & Historic Fredericksburg

Time:

9:00am–2:00pm

Date:

Wednesday, September 22

Time:

9:00am–4:00pm

Location: Departs from the Hotel Lobby Fee:

$70.00 before 8/1/21, $90.00 after 8/1/21 (Includes: Transportation, lunch and guided tour)

Location: Departs from the Hotel Lobby Fee:

San Antonio Missions National Historical Park, along with the Alamo Mission, are designated a UNESCO World Heritage Site. These Catholic missions (Mission Concepción, Mission San Jose, Mission San Juan, Mission Espada, and the Alamo) were established by Spanish priests along the San Antonio River to serve as the center of an ethnically diverse society. Today, the missions represent the largest concentration of Spanish colonial missions in North America. After the missions guided tour, enjoy lunch at Boudro’s Texas Bistro, one of the most treasured and popular attractions on the San Antonio River Walk since 1986.

$130.00 before 8/1/21, $150.00 after 8/1/21 (Includes: Transportation, Lunch and Wine Tasting)

Immerse yourself in history! Fredericksburg’s founders knew this was someplace special when they planted roots here in 1846. Behind the elegant shops and fine dining, you can feel the authentic German heritage in the historic buildings along Main Street, the German cuisine, and the welcoming spirit of the people. Called the “Shopping Haven” for its handmade jewelry, antiques, artwork, gifts, and much more. Farm-to-table dining is the norm in Fredericksburg, as the area has deep roots in agriculture and is home to some of the best farms, orchards, and wineries. You will enjoy an authentic German meal at Der Lindenbaum located in a beautiful historic limestone building built by the German pioneers over a century ago. Wine production in Fredericksburg dates back to the original settlers who used the native mustang grape to produce wines. We will visit Becker Vineyards, where you will experience first-hand the wine-making process during a private estate tour and wine flight tasting. The winery, located in a 19th century German stone barn reproduction, is surrounded by lavender fields. Summer 2021

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AEG2021 – ANNUAL MEETING PREVIEW

Guest Tour 3 San Antonio Riverwalk & Briscoe Western Art Museum Walking Tour

Guest Tour 4 Natural Bridges Cavern Date:

Friday, September 24 9:05am–2:00pm

Date:

Tuesday, Sept. 23

Time:

10:30am–2:30pm

Location: Departs from the Hotel Lobby

Location: Departs from the Hotel Lobby Fee:

Fee:

$70.00 before 8/1/21, $90.00 after 8/1/21 (Includes: Transportation, Lunch, Riverboats, and Museum Tour)

$120.00 before 8/1/21, $140.00 after 8/1/21 (Includes: Transportation, Lunch, and Cavern Tour)

We will begin the tour with a stroll from the hotel along the winding path of the San Antonio River Walk. Experience the magical powers of the nation’s largest urban ecosystem as you soak in the history and ambiance on a 35-minute guided riverboat tour. Enjoy lunch under the colorful umbrellas of the Spanish colonial period hacienda, Casa Rio, located on the banks of the river. After lunch we will tour the Briscoe Western Art Museum. Located on the banks of the historic San Antonio River Walk, the museum brings to life the vibrant culture and heritage of the Western United States. The museum provides visitors from San Antonio and beyond the opportunity to experience its permanent collection of Western art and artifacts depicting the American cowboy, American Indian, the Vaquero, and the many diverse cultures that forged the American West. After the tour you can enjoy the museum and River Walk shopping on your own.

Enjoy the otherworldly formations of the Natural Bridge Caverns formed by single drops of water and the slow passage of time. Our custom tour will be guided by the cave geologist. State-ofthe-art lighting illuminates the massive underground chambers that are 180 feet below the surface. See awe-inspiring ancient formations centuries in the making and still growing today, such as stalagmites, stalactites, flowstones, chandeliers, and soda straws. Walking distance is three-quarters of a mile and includes stairs. Cavern temperature is 70°, and the relative humidity is 99%. Enjoy lunch at the Cavern Café in the Discovery Village. Shop for gifts and unique souvenirs at the Trading Post—with one of Texas’ best collections of rocks and minerals from around the world. Light outdoor clothing and walking shoes recommended. 18

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AEG2021 – ANNUAL MEETING PREVIEW

Special Event

Evening on the Paseo del Rio (River Walk) Wednesday, September 22, 6:30–9:30pm $130/person Join us for an evening on the beautiful San Antonio River. We will begin at dusk with a cruise on the river in open-air barges. Enjoy cocktails and other beverages for a relaxing hour as the lights along the River Walk begin to sparkle.

There is no official dress code, but we recommend dressy casual to semi-formal attire in keeping with the venue’s setting. As always, layers are recommended— though the river cruise will be warm, the venue is, of course, air conditioned.

The barges will drop us off right at the Briscoe Western Art Museum where we will then enjoy nouvelle Mexican cuisine in The River View Room, situated on the first floor of the museum’s Jack Guenther Pavilion. The pavilion brings together exquisite modern architecture—luscious white oak paneling and rich earth tones—an idyllic location, and floor-to-ceiling windows offering stunning vistas and unparalleled views of the River Walk. Its attached patio with waterfall cascading into the river creates an outdoor setting that is sure to delight.

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AEG2021 – ANNUAL MEETING PREVIEW

Optional Events

Technical Program

Young @Heart Student/Professional Special Event

Technical Sessions and Symposia ■

Coastal Hazards

Tuesday, September 21, 8:00–10:00pm

■

Dams and Levees – Risk-n-the-River

Students Attend Free, All Others $15

■

DEIC/Diversity

This social event is a great way to start your week in San Antonio. Take this opportunity to meet many of our Student Members in the environmental and engineering geology sciences while you enjoy free appetizers (and a free drink ticket if you arrive early!) Just a short walk from the hotel, this event is an excellent opportunity to recruit future Chapter members, meet potential employees, find a student to mentor, and see the future of AEG. We encourage young professionals to join the event and welcome experienced professionals who are “young at heart!”

■

Environmental – Topic: 1,4 Dioxane

■

GeoUAS (Drones)

■

Geologic and Seismic Hazards (GASH) – Evaluating Geologic and Seismic Hazards and the Potential Need for Hazard Mitigation

■

Geophysics

■

Groundwater and Karst

■

Landslides – Line ‘em up but don’t knock ‘em down! Landslide Investigation and Mitigation for Linear Infrastructure Projects

■

Subsidence

■

Tunneling

Women in AEG/AWG Diversity Luncheon Thursday, September 23, 12:00–1:30pm $50 per person Join us for this networking event that focuses on diversity and inclusion issues in the industry and offers an open forum for discussion and education. Men are, of course, welcome to attend!

Annual Banquet Thursday, September 23, 7:00–10:00pm $100 per person This is a well-attended, high-profile event at which the Association's major awards are given. Join us for a gourmet dinner, fine wine, and a chance to visit with friends—both old and new. Semi-formal attire is recommended, though not required.

Awards Ceremony and Corporate Business Meeting Friday, September 24, 3:40–5:00pm Included with all registration types The Awards Ceremony and Corporate Business Meeting is a time for Association officers, board members, and committee members to participate, report on their activities, witness the installation of new officers, the transition of the outgoing and incoming Presidents, and the presentation of some of the AEG and AEG Foundation awards.

We are still accepting abstracts for Poster Presentations and the following Oral Presentations: ■

Subsidence/Karst/Groundwater

■

Landslides

■

Coastal Hazards

■

GeoUAS (Drones)

■

Geophysics

Full information can be found at: https://www.aegannualmeeting.org/technical-sessions

Consider Becoming a Sponsor of the 2021 Annual Meeting Sponsor Opportunities start for as little as $100 and can increase your company or organization’s visibilty during the meeting and beyond.

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AEG2021 – ANNUAL MEETING PREVIEW

Student Opportunities Annual Meeting Mentor Program The Student and Young Professional Support Committee (SYPSC) is developing a mentor program to pair professionals that plan to attend the 2021 Annual Meeting with interested student attendees. We hope mentors can provide advice and support both before and during the Annual Meeting to make the meeting more relaxing, enjoyable, and beneficial for students. Students interested in being aired with a mentor will identify themselves when they register for the meeting and will be provided with the contact information of a professional who has volunteered to be a mentor. The student can then contact the professional with questions ranging from “What should I wear?” to “Could we meet during the Ice Breaker?”

Student/Professional Networking Reception Tuesday, Sept. 21, 5:15–6:30pm Be sure to attend this fun and relaxed event as it is the perfect place for you to make new friends and meet future employers/employees! You don't want to miss it! Be sure to sign up on your registration form.

Young @Heart Student/Professional Special Event Tuesday, Sept. 21, 8:00–10:00pm

Registration Rates and Deadlines Rate Full Registration

by 8/1/21

after 8/1/21

AEG Member

$495.00

$595.00

Non-Member

$645.00

$745.00

AEG Student Member

$95.00

$125.00

Events included with Full & Student Registrations: - Student / Professional Networking Reception - Icebreaker Reception with drink ticket and appetizers - Exhibitor Hosted Luncheon - Poster Session Reception with drink ticket - Opening General Session - All Technical Sessions and Symposia - Exhibit Hall with All-Day Coffee and Technical Session Breaks

Guest Registration Must be linked to a full or one-day registration Per Adult $150.00 $175.00 Events included with Guest Registration: - Icebreaker Reception with drink ticket and appetizers - Exhibit Hall with All-Day Coffee - Ability to sign up for Guest Tours

One-Day Registration

Students Attend Free This social event is a great way to start your week in San Antonio. Make or Mingle with friends in environmental and engineering geology while you enjoy free appetizers (and a free drink ticket if you arrive early!) Just a short walk from the hotel, this event is an excellent opportunity to build connections with peers, mentors, senior fellows, and potential employers. We encourage students and young professionals to join the event and welcome experienced professionals who are “young at heart!”

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Summer 2021

AEG NEWS 64 (3)

PROFESSIONAL CONTRIBUTIONS

50 Years of Paleoseismology: The Science and the Business

James P. McCalpin and Eldon M. Gath

he modern era of Paleoseismology arguably began 50 years ago, shortly after the 1971 San Fernando, California earthquake (M6.6). This was the nation’s most damaging urban earthquake since the 1933 Long Beach earthquake (M6.4), and the first to occur after active fault studies for nuclear power plants had begun in the mid-1960s (e.g. Schlocker et al., 1963).

Paleoseismology, the Science Paleoseismic studies in the 1970s studied deformation along the traces of known faults, some of which had experienced historic surface ruptures. These “tectonic geomorphology” studies did not involve trenching the fault trace (which came later), but nevertheless yielded the first crude estimates of active fault parameters needed for seismic hazard analysis (e.g. Wallace, 1970). USGS continued this geomorphic emphasis up to 1977, when the National Earthquake Hazards Reduction Program (NEHRP) was created. In addition to the USGS Internal Program, the NEHRP External program for academics and consultants was more applied, relying more on trenching and studying fault hazards in hitherto unstudied (or under-studied) geographic areas. External studies discovered many previously unknown Holocene-active faults, which paved the way for the Quaternary Fault and Fold Database of the USA. http://bit.ly/earthquakehazards Because Paleoseismology developed during the past 50 years, we can observe how the field underwent a stairstep evolution of rapid advances (triggered by new techniques), separated by plateaus in which the new techniques were applied to studies over large geographic areas (Figure 1). The 1970s fault-centric nature of paleoseismic studies has continued to this day and has advantages and disadvantages. Such “primary” studies do yield the seismic source parameters for individual faults (surface rupture length, displacement per event, slip rate, recurrence interval, maximum/characteristic magnitude) needed for seismic hazard analysis (SHA), which is a forward model (from cause to effect). The weakness of the method is if active faults exist in the studied area that are not known, the seismic hazards are underestimated. This is particularly true in areas of blind faulting, or where the characteristic earthquake magnitude is at or below the threshold for surface rupture (M~6). The alternative approach is to study a site’s record of strong ground shaking directly, as preserved by evidence of prehistoric liquefaction and/or other ground failures (landslides, lateral spreads, toppled rocks, etc.). This “secondary” approach is not affected by the problem of unknown active faults. It does have three weaknesses, however. First, most sites are not particularly susceptible to liquefaction or ground failure. Second, the size of observed

Figure 1. New techniques (vertical lines) that have advanced Paleoseismology; black, dating methods; medium gray, remote sensing methods; light gray, institutional changes. Impact on the science is reflected by the height of vertical lines (in our subjective viewpoint). Curved arrows show how later advances in a single technique (luminescence dating) have superseded earlier methods. C-14 calib, calendar-correction of radiocarbon ages; LSAP, Low-Sun-Angle Photography; TL, thermoluminescence dating; AMS, Accelerator Mass Spectrometry radiocarbon dating; OSL, Optically-Stimulated Luminescence dating; CRN, Cosmogenic Radionuclide dating; Digital Elevation Models; SAR, single aliquot or single grain luminescence dating; ALS, Airborne Laser Scanning (lidar); TLS, terrestrial lidar; SfM, structure from motions DEMs; UAVs, unmanned aerial vehicles (drones).

liquefaction/ground failure features, based on historic observations, does not scale linearly with the strength of ground shaking. Third, liquefaction and ground failure can be triggered by nonseismic means. As a result, current predictions of probabilistic fault displacement hazards (PFDHA) and probabilistic ground motions (PSHA) are built from fault-specific evidence, with usually no regard for the presence or absence of secondary evidence at (or near) the site, even used as a reality check on the forward model results.

What About Interpretive Paradigms? A new interpretive paradigm (e.g., plate tectonics) can have a bigger scientific impact than any one new field or laboratory technique. New paradigms often arise from new types of data, which themselves became possible from a new technique (e.g., Figure 1). A recent example is surface rupture patterns and their prediction by PFDHA. At present, predictive relationships for surface rupture are based solely on empirical data (i.e., no underlying physical or kinematic model). Not surprisingly, predicted outputs carry high uncertainty. The new remote sensing

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PROFESSIONAL CONTRIBUTIONS techniques mentioned in Figure 1 (ALS, TLS, SfM, UAVs) permit mapping every tiny rupture trace, resulting in hundreds to thousands of rupture traces defined, and point displacements measured. For example, the Norcia, Italy, rupture of 2016 yielded 5,400 point measurements of displacement, most on distributed faults. Such data densities were not possible previously but are statistically robust enough to support development and testing of physical/kinematic models of principal and distributed faulting. For example, fault rupture may be partly controlled by depth to bedrock or by the rheology of the surface materials, neither of which are used in present PFDHA models. Underpinning PFDHA with a physical model should, in theory, decrease the uncertainty in predicted fault trace length, location, and displacement, because data points that clearly contradict the physical model can be deleted. But will the final uncertainty become small enough that engineering geologists and their owner/clients will rely upon them for site specific design and hazard mitigation? This is where the academic aspirations run into the practical business realities of cost-benefit analysis.

Science Outlook for the Future What are the most likely near-term scientific advances? Based on trends of the first 50 years, advances will probably occur in dating methods, remote sensing, and perhaps geophysics: 1) Rapid Dating (within a few days), so dates can be known before the paleoseismic trench must be backfilled. This would prevent the syndrome of “Oh, if I would have known that faulted bed was Holocene, I would have….” Commercial labs currently offer “rush” AMS radiocarbon dating within one week, but for luminescence dating even “rush” dating takes months. Few practitioners can get permission to leave a trench open for months, so a more rapid dating turnaround would help with trench interpretation. 2) “Virtual Trenching” via shallow geophysics. Twenty years ago, attempts were made to log stratigraphy and structure beneath normal fault scarps using P- and S-wave seismic tomography, which was touted as “seismic trenching” (e.g., Sheley et al., 2003). However, the tomograms could not distinguish thin or small deposits or displacements, which were easily visible on the log made by conventional trench logging. This research thread has stalled in the past decade, but should be taken up again, because as urban fault traces become totally developed, traditional trenching is no longer possible. One possibility to maintain high resolution with depth is to augment surface geophysical surveys with downhole surveys, which can use wave-guide principles to trace subsurface deposits between boreholes. This could potentially increase the depth of detailed fault-zone imaging to tens of meters, regardless of depth to water table. 3) New remote sensing techniques that image the shallow subsurface. Just as lidar penetrates surface vegetation to reveal the bare-earth topography, a useful advance would be an aerial sensor that penetrates the upper few meters of the subsurface and can measure its material properties (density, moisture, dielectric properties). Such a sensor could directly image Summer 2021

young, low-density materials deposited in topographic traps (grabens, ramps) in active fault zones, even where the traps have no surface expression today because they are filled with sediment. These are good trenching targets. 4) Refined methods to identify and analyze the paleoseismic signature of M<6 earthquakes. Californians have been waiting 110 years for a repeat of an M8 earthquake on the San Andreas. But for every M8 earthquake in a seismic cycle, there will be 10 M7s and 100 M 6s (think of San Fernando M6.6; Whittier Narrows, M6.0; Coalinga M6.2; Loma Prieta, M6.9; Northridge, M6.7; South Napa, M6.0). The cumulative damage from 100 such M6s will be as large or larger than a single M8. But the evidence is much smaller and harder to find. 5) Increased usage of secondary paleoseismic evidence (liquefaction, ground failures) to provide reality checks in PSHA (e.g., Fan et al., 2019).

Paleoseismology, the Business Business needs for paleoseismic studies are separate from and independent of the science advances, which take place in academia and in government agencies (public policies based on new knowledge and experiences). The business need (or opportunity for paleoseismologists) is thereby generated by these public policies and regulations, while the engineering geologist’s ability to comply and solve their client’s problems is, to a large degree, facilitated by the scientific advances of the academic paleoseismology community. Unfortunately, these advances are often under the radar of the practicing engineering geology practitioner, or to quote Dr. Kerry Sieh in 2000, “the state of the knowledge is at least 10 years ahead of the actual use of that knowledge” (Yeats and Gath, 2005). This lag time led to the development of technical specialists in the applied paleoseismology discipline, perhaps starting as far back as Dr. Roy Shlemon and the fledgling California nuclear power industry in the mid-1970s.

Historically Dominant Market Sectors Paleoseismic projects range over several market sectors: Water-related (Dams, Aqueducts, Tunnels); Energy-related (power plants, including nuclear; extraction sites, such as offshore drilling platforms; pipelines and terminals, such as LNG terminals); Waste disposal-related (high-level and low-level nuclear waste repositories; landfills); Transportation (highways, railroads); Land development-related (residential, commercial). In the 1960s–70s nuclear projects dominated the market at large scales, whereas in 1973 California’s Alquist-Priolo Fault Zoning Act required small-scale “paleoseismic” studies for residential and commercial land-use changes. The smaller budgets of the residential studies were offset by their sheer numbers (thousands), so cumulatively they were as important as the large-scale projects for critical facilities.

Paleoseismic Studies Driven by Regulations Engineering geologists were aware of the fault rupture hazard before there was a scientific method to quantify that hazard

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PROFESSIONAL CONTRIBUTIONS sufficient for risk reduction. Indeed, even the Alquist-Priolo Act was silent on the possibility of quantitative paleoseismology, requiring instead the strict avoidance (setback zone) from any Holocene-age faults. The Act was silent because the science did not yet exist from which to understand prior fault rupture timing, displacement magnitude, or even its spatial locations. The only mitigation permitted by law in California was, and unfortunately still is, strict structural avoidance. Since 1973 therefore, even though huge advances in paleoseismology have been made within the academic community, most engineering geologists in California have little need for them. Is this sediment layer or buried paleosol (soil) horizon Pleistocene or Holocene, and is it faulted or not? Period. But large engineering projects are not necessarily subject to the limitations within the Alquist-Priolo Act, and structural mitigation for fault rupture displacement does look to paleoseismology to help answer design questions such as displacement magnitudes, kinematics, most recent event and knowledge of recurrence intervals. Of course, all of these parameters are unlikely to be obtained from any single study site, so it is also necessary for the practitioner to be able to define the uncertainties in a manner that can be used by the design engineer and understood by the project’s reviewers. Specific examples of these kinds of projects involve cutting the U.C. Berkeley football stadium in half to accommodate the Hayward fault’s current creep rate and future earthquake rupture, PG&E’s ongoing natural gas pipeline risk studies at fault crossings, and LA Metro’s fault rupture mitigation program for its subway tunnels.

The past 20 years has been a drought cycle in much of the western United States, and with the westward population shift from COVID-19, metro areas of the West are scrambling for new water supplies. At this time, Lakes Mead and Powell on the Colorado River contain only 37% and 34% of capacity, respectively. Lower levels will trigger a Lower Basin “water shortage condition,” resulting in decreased water allotments to Arizona, Nevada, and Mexico. This will spur new dam projects, pipelines, and aqueducts in earthquake country. Regulatory Changes

Predicting business trends in paleoseismology is even more uncertain than predicting its scientific advances. The current trending concerns are described below.

California geologists hope to someday be able to use their paleoseismic tools and expertise under a modernized AlquistPriolo Act which opens up the mitigation alternatives to more than just avoidance. In the almost 50 years since its passage, its interpretation by regulators and state geologists has become increasingly prescriptive (Gath, 2015), while engineering mitigation of ground deformation has become increasingly performance and risk based, relying on huge increases in computer power for modeling, mechanical testing, materials science, and learning from earthquake studies to improve their professional practice (Committee, 2003). If engineering geologists were able to apply the current knowledge base in paleoseismology techniques to their projects the increase in knowledge for all of California’s faults would increase exponentially because now there would be hundreds if not thousands of projects per year wherein rupture recurrence, kinematics, and magnitudes would be built into the investigation plan and budget as it would finally be important for design and engineering mitigation. If the displacements exceed the capacity for mitigation, avoidance is still an option, but until engineers are allowed to try, paleoseismic-level geologic investigations cannot be defended as standard of care.

Market Sectors

References

Many countries have recently pledged to reduce or eliminate fossil fuels as a source of energy in favor of renewable energy, within the next decade or two. If this occurs (it will be expensive), it will reduce paleoseismic projects from the fossil fuel sector, such as oil and gas pipelines, offshore drilling rigs, and possibly nuclear power plants and waste repositories (after all, uranium is not a renewable energy source). The transition to renewable energy for stationary facilities (residential, commercial, industrial) and transportation (autos, Elon Musk’s Hyperloop, long-haul trucks, high-speed trains, airplanes) is basically a transition to electrical energy. Today electricity is generated by fossil-fuel powered, industrial-scale plants (=critical facilities), many of which require geologic hazard studies. In contrast, much future renewable electricity will be generated at widely dispersed points of use, which will not require geologic hazard studies. In the transportation sector, the increased speed of electrical vehicles such as high-speed trains may trigger a requirement for studying small ground movements, including tectonic ones. The amount of allowable track deflection for a 200–300-mph electric train is much smaller than for a 55-mph Amtrak coach.

Committee to Develop a Long-Term Research Agenda for the Network for Earthquake Engineering Simulation (NEES), 2003, Preventing earthquake disasters: The grand challenge in earthquake engineering: A research agenda for the Network for Earthquake Engineering Simulation (NEES); National Academy of Science, National Research Council, Board on Infrastructure and the Constructed Environment, 138 p. Fan, X. and 16 others, 2019, Earthquake-induced chains of geologic hazards; patterns, mechanisms, and impacts: Rev. Geophys. 57: 421–503. Gath, E.M., 2015, Is the California Geological Survey’s position on active fault zoning and mitigation logical or ethical in light of 40+ years of earthquake geology research? (abs); Geol. Soc. Amer. Abstracts with Programs: 47(7):192.192. Schlocker, J., Bonilla, M.G. and Clebsch, A., Jr., 1963, Geologic and seismic investigations of a proposed nuclear power plant site on Bodega Head, Sonoma County, California; Part I, Geologic Investigations: U.S. Geol. Surv. Trace Element Invest. Report TEI-837, p. 1–42. Sheley, D., Crosby, T., Zhou, M., Giacoma, J., Yu, J., He, R., and Schuster, G.T., 2002, 2D seismic trenching of colluvial wedges and faults: Tectonophys. 268(1): 51–69. Wallace, R.E., 1970, Earthquake recurrence intervals on the San Andreas fault: Geol. Soc. Amer. Bull. 81(10): 2875–2890. Yeats, R.S. and Gath, E.M., 2005, Paleoseismology of surface ruptures: research tool or standard of practice?: Association of Environmental & Engineering Geologists, AEG News, March, 2005, p. 21–23.

Business Prospects for the Future

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PROFESSIONAL CONTRIBUTIONS

About the Authors James McCalpin, BA 1972, University of Texas; MS 1975, University of Colorado; PhD 1981, Colorado School Mines, has worked in applied geomorphology, geohazards, and paleoseismology since 1976. He was County Geologist of Jefferson County (CO) in 1981–82, then taught geomorphology and engineering geology 1982–91 at Utah State University. Dr. McCalpin founded GEO-HAZ Consulting, Inc. in 1991 and has since performed nearly 200 consulting projects for clients worldwide. He has authored more than 160 papers in refereed journals and proceedings, 13 published geologic maps, and >130 consulting reports on geohazards for clients. His 1996 book Paleoseismology (Elsevier Publishing) won the AEG Holdredge (1999) and GSA Burwell (2000) awards. Paleosesismology 2nd Edition has been published in English (2009), Russian (2011), and Chinese (2020).

Eldon Gath, Founder and President of Earth Consultants International of Santa Ana, California, is a Past-President and Life Member of AEG. He served on the AEG Board of Directors from 1990–98 and 2016–19, was the 2014–15 Jahns Lecturer, and granted the Floyd T. Johnston and E.B. Burwell awards. He has served on numerous technical committees and advisory boards for the US Geological Survey, National Research Council, Southern California Earthquake Center, State of California, IAEG, EERI, and others. Eldon has worked on projects throughout California and other western states, and in a dozen countries as diverse as Japan, Papua New Guinea, Panama, and Turkey. His projects have included gas storage fields, oil field redevelopment, city and county hazard management plans, pipelines, canals, dams, tunnels, and hundreds of “typical” engineering geology studies for development planning, design, and construction.

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PROFESSIONAL CONTRIBUTIONS

The Role of Paleoseismic Investigations in the Engineering of Pipeline Fault Crossings James Hengesh, Douglas Nyman, and David Waring

Introduction

ipelines are geographically distributed systems that cross a variety of geological environments and are exposed to a diverse range of ground conditions and geological hazards. These hazards must be characterized for the route selection, basic design, detailed design, and construction stages of a project. Experience has proven that failing to recognize and mitigate geological hazards for pipeline projects can result in a loss of pipeline integrity leading to direct costs from pipeline damage, environmental impacts, repair and monitoring costs, and indirect losses due to business interruption (Lee et al., 2009). For example, several segments of the Trans-Ecuador oil pipeline in the Matagua River Valley, Ecuador, were severed and dislocated tens of meters by flow failures during the 1987 Mw 7.1 Ecuador earthquake (Nieto et al. 1991). Costs associated with repairs and lost revenue from the 1987 earthquake reached roughly U.S. $1 billion (1987 dollars; O’Rourke and Liu, 1999). Fault crossings are significant because pipelines that cross a surface fault rupture must deform longitudinally and in flexure to accommodate the associated permanent ground deformation (Nyman and Bouckovalas, 2019; Honegger and Nyman, 2017). If a pipeline crosses a potentially active fault, it is necessary to characterize its activity, location, orientation, amount and type of potential displacement, slip characteristics, and zone of disturbance. Paleoseismic investigations can play a key role in determining the activity of a fault and parameters needed for pipeline engineering and design.

8. Design fault displacement (defined as orthogonal components of displacement in three-dimensional space); 9. Detailed topographic profile; and, 10. Soil types and geotechnical parameters in the locality of the fault crossing. Compiling the above information requires that geological investigations be carried out to provide the engineer with the information necessary for design of the fault crossing.

Investigative Approaches Geological and Geomorphological Mapping Approach Up through the 1990s, the geological investigations carried out in support of pipeline engineering projects tended to be limited to geological and geomorphic mapping. This approach can be sufficient if there are Quaternary-age deposits or geomorphic surfaces that cross a fault zone. Figure 1 shows an example of a Quaternary age depositional surface that is offset by faulting. In other cases, the continuity of deposits or landforms may provide evidence of the absence of tectonic activity and thereby confirm that an engineered pipeline fault crossing design is unnecessary. Surficial geological mapping has successfully provided information to support engineering analyses and design of mitigation measures for major pipeline systems. For example, the geological investigations carried out for the Trans-Alaska Pipeline System (TAPS) in 1973 successfully identified the locations of the Denali fault (Cluff et al., 2003). The information

Data Requirements for Characterization of Fault Crossings Once it is confirmed that an existing pipeline or proposed route crosses an active fault, it is necessary to evaluate the fault’s characteristics to support the engineering and design of the fault crossing mitigation measures. At a minimum, the following information is required to characterize active fault crossings: 1. Fault activity and slip rate; 2. Location of the main fault trace, secondary splays, and width of permanent ground deformation zone; 3. Fault geometry – strike direction and dip angle; 4. Style of faulting – strike-slip, normal, reverse, or oblique; 5. Slip partitioning among fault splays; 6. Fault length, width, area, and displacement distribution per surface rupture event; 7. Maximum earthquake magnitude distributions and recurrence intervals; 26

Figure 1. Given suitable deposits and exposures a faults location and sense of deformation can be estimated based on field observations. At this location in Owens Valley, California, the 767 Ka Bishop Tuff and late Quaternary fluvial terrace deposits (black arrows) are offset (red arrows); note the left-lateral oblique offset of Owens River Gorge. Oblique aerial view to southeast.

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PROFESSIONAL CONTRIBUTIONS developed during these investigations was used to support the engineering of the TAPS pipeline at the fault crossing. In 2002, the fault crossing design for the Denali fault was tested. The Mw 7.9 Denali earthquake produced 5.5 m of ground displacement at the TAPS crossing location consistent with the estimated 6.1 m design displacement. The mitigation measures put in place at the Denali fault crossing enabled the pipeline to successfully accommodate the permanent ground deformation produced by the event (Sorensen and Meyer, 2003; Hall et al., 2003). Characterizing a fault using only a surficial mapping approach can be challenging in a number of situations, such as: along low activity faults; in areas with poor exposure; at locations that lack suitable Quaternary deposits or morphological features; and where the style of deformation may be complex. The accurate determination of 3D fault slip vectors is essential for establishing an optimal pipeline crossing alignment or analyzing an existing crossing. Thus, in most cases, reliance on surface mapping alone is insufficient for definition of displacement parameters, and there is a clear role for paleoseismic trenching investigations.

Paleoseismic Trenching Approach Paleoseismic trenching is one of the most effective techniques for evaluating surface fault rupture hazards that may impact pipelines. A trench exposes the stratigraphic and structural features in the shallow subsurface along the fault zone (Figure 2a) and enables the direct observation, description, measurement, and dating of critical features. The purpose of a trenching investigation is to determine the precise location where a pipeline crosses a fault, and to document the fault’s activity, orientation, style of faulting, and amount of displacement expected during an earthquake. Where conditions are favorable, trenches also can yield information on dates of past surface rupturing events, earthquake recurrence intervals, fault slip rates, and slip vectors (Figure 2b). One of the principal benefits of fault trenching for pipeline projects is the ability to more reliably characterize key input parameters to support engineering activities. We recently carried out paleoseismic trenching investigations along several existing

pipelines to validate fault locations and design parameters for faults that previously were assessed using only surface mapping techniques. Although the surface mapping was carried out by experienced geologists, the limitations of the approach included residual uncertainties in fault location, activity and style of deformation. The fault validation trenching program resulted in significant revisions to the interpretations of fault parameters that were developed based on surface mapping. The results of the trenching revealed the following: ■ Some faults previously assessed as active did not meet the criteria of Holocene activity; ■ Some previously mapped fault traces were mislocated; and, ■ The previously interpreted fault geometry, style of deformation and slip vectors were incorrect. Data from the paleoseismic trenching program reduced the uncertainties associated with the input parameters needed for fault crossing engineering. This information has led to design of fault crossing mitigation measures where the pipelines have significantly greater displacement capacity and a much lower residual risk of losing pressure integrity.

Supporting Risk Assessments Owners of large pipeline systems are now completing systemwide risk analyses to assess their corporate exposure to a range of potential impacts. These risk analyses typically include a broad range of operational and environmental issues, including geohazard events. Because paleoseismic trenching provides the opportunity to document a fault’s movement history and to sample and date materials related to past earthquakes, fault slip rates and earthquake recurrence intervals often can be assessed. These data can yield an annualized frequency, or rate of earthquake occurrence that may be incorporated in the risk assessments. By combining the displacement capacity of the pipeline at a fault crossing with the rate of occurrence of the design earthquake, the residual risk of pipeline failure (defined as loss of pressure integrity) can be assessed (Figure 3—next page). This residual risk of failure can be incorporated into a company’s overall risk assessment. In areas where fault crossing mitigation measures have not been put in place, this type of risk assessment also can be used to communicate within a corporate risk framework that areas of high risk exist, and to identify and prioritize locations for future investigation and mitigation.

Conclusions

Figure 2. (a) Example of paleoseismic trench completed to investigate a potential pipeline fault crossing; (b) fault zone (white arrows) exposed in trench showing horizontal slip vectors on fault plane (black arrow). Summer 2021

Paleoseismic trenching investigations have been completed along several existing pipeline routes where fault crossing designs were based on fault characterizations sourced from surface geological and geomorphological mapping. The results have shown that the surficial mapping approach can have large uncertainties that may lead to: (i) inaccurately identifying the location of an active fault trace; (ii) inferring that a nontectonic feature is fault related; (iii) incorrectly assessing that an older fault is Holocene active (or vice-versa); (iv) mischaracterizing the fault orientation, style of deformation, and 3D slip vectors

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PROFESSIONAL CONTRIBUTIONS

References Cluff, L.S., Page, R.A., Slemmons, D.B., and Crouse, C.B., 2003, Seismic hazard exposure for the Trans-Alaska Pipe-line, in Beavers, J.E., ed., Advancing mitigation technologies and disaster response for lifeline systems: ASCE, Sixth U.S. Conference and Workshop on Lifeline Earthquake Engineering, ASCE Technical Council on Lifeline Engineering, August 10– 13, Long Beach, CA, p. 535-546. Hall, W.J., D.J. Nyman, E.R. Johnson, and Norton, J.D., 2003, Performance of the Trans-Alaska pipeline in the November 3, 2002 Denali fault earthquake, in Beavers, J.E., ed., Advancing mitigation technologies and disaster response for lifeline systems: ASCE, Sixth U.S. Conference and Workshop on Lifeline Engineering, August 10-13, Long Beach, CA, p. 522-534. Honegger, D.G., and Nyman, D.J., 2017, Pipeline design and assessment guideline (2017 Revision): Pipeline Research Council International, Inc., Catalog No. L51927-R01. Lee, E.M., Audibert, J.M.E., Hengesh, J.V. and Nyman, D.J., 2009, Landsliderelated ruptures of the Camisea pipeline system, Peru: Quarterly Journal of Engineering Geology and Hydrogeology; v. 42, p. 251-259, doi:10.1144/1470-9236/08-061. Nieto, A.S., and Schuster, R.L., Plaza-Nieto, G., 1991, Mass wasting and flooding: in Chung, R.M., ed., The March 5, 1987, Ecuador earthquakes, mass wasting and socioeconomic effects: National Research Council, Natural Disaster Studies, v. 5, p. 51-82, National Academy Press, Washington, D.C. Nyman, D.J., and Bouckovalas, G.A., 2019, Assessment and mitigation of seismic geohazards for pipelines, in Rizkalla, M., and Read, R., eds., Pipeline geohazards: planning, design, construction and operation, ASME, Chapter 11. O’Rourke, M.J. and Liu X., 1999, Response of buried pipelines subject to earthquake effects: MCEER Monograph No. 3, 247p. Sorensen, S.P., and Meyer, K.J., 2003, Effect of the Denali fault rupture on the Trans-Alaska Pipeline,” in Beavers, J.E., ed., Advancing mitigation technologies and disaster response for lifeline systems: ASCE, Sixth U.S. Conference and Workshop on Lifeline Earthquake Engineering, August 10-13, Long Beach, CA, p. 576-586.

About the Authors

Figure 3. Example of probability of failure analysis for a mitigated pipeline fault crossing. Figure courtesy of GR8 GEO.

for a fault crossing; and (v) inaccurately estimating fault slip rates and recurrence intervals. All of these uncertainties can affect project engineering and the quantification of risk. Incorrectly characterizing the fault parameters can result in misplacement of pipeline crossing mitigation measures, unfavorable alignment of the pipeline across the zone of deformation, and inadequate pipeline displacement capacity to accommodate ground surface rupture. The longterm effect is that the pipeline system may have considerably greater residual risk of failure than if resources were invested at the start of the project to develop reliable inputs to support subsequent engineering activities. Although each fault location is unique and needs to be assessed on a case-by-case basis, the results of our field investigations have clearly demonstrated the value of paleoseismic trenching. The data developed during trenching programs support of the implementation of robust engineering mitigation measures that reduce the risk of failure at pipeline fault crossings.

James Hengesh, Principal Geologist at Interface Geohazard Consulting, has 34 years of experience conducting investigations to characterize geological and seismic hazards for major infrastructure projects worldwide. Dr. Hengesh has served as technical leader and expert reviewer for assessments of both onshore and offshore pipelines. He has characterized surface fault rupture hazards to support engineering analyses and design of mitigation measures for pipelines in Alaska, Albania, Australia, Azerbaijan, Georgia, Greece, India, Papua New Guinea, Peru, Russia, Tanzania, Trinidad, and Turkey. Douglas Nyman, Principal Engineer of D.J. Nyman & Associates, has 45 years of experience in the mitigation of earthquake and geological hazards for pipeline systems. He provides engineering services to support design of onshore and offshore pipelines to withstand large ground displacements and extreme or unusual load conditions. David Waring is an Engineering Geologist, who graduated from Imperial College London. David is currently employed by BP and provides onshore geotechnical and geohazard technical assurance for projects and operational sites across the integrated energy company.

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iPad Lidar Scanning for 3D Trenching: A New Methodology for Paleoseismologists Demonstrated on the Dog Valley Fault, Truckee, California Ian K.D. Pierce and Rich D. Koehler

Introduction

he advent of Structure-from-Motion (SfM) photogrammetry has revolutionized the acquisition of cheap, rapid, and accurate 3D full color data for a wide variety of tectonic and geomorphic studies (e.g., Westoby et al., 2012; Reitman et al., 2015; Angster et al., 2016; Pierce et al., 2021; Delano et al., 2021). SfM is now the preferred methodology for producing detailed and accurate trench photomosaics. One of the problems facing this application is a lack of a local reference or scale. Various methods have been developed to counter this, including the use of highly accurate, but labor intensive and costly survey equipment (e.g.: Reitman et al., 2015) or scale bars placed in the scene (e.g.: Delano et al., 2021). Here we demonstrate a new methodology using the laser scanner built into a 2020 iPad Pro to provide reference and accurately scale SfM models. For this study, we focus on the Dog Valley fault north of Lake Tahoe, California, and present reconnaissance fault trace mapping (lidar- and fieldbased) and preliminary paleoseismic trenching results from an exposure along the eastern end of the Dog Valley fault. This ongoing work will contribute towards a better understanding of regional seismic hazards and the role of the Dog Valley fault in accommodating strain in the northern Walker Lane.

The Dog Valley Fault The Dog Valley fault in northeast California is a northeaststriking, left-lateral strike-slip fault that extends for ~25 km from north of Truckee, California, to the north flank of Peavine Mountain near Reno, Nevada (Figures 1 and 2). At this latitude, about 10 to 15 percent (5–7 mm/yr) of Pacific/North American plate relative motion (dextral shear) is distributed across the northern Walker Lane with about 2–3 mm/yr concentrated along its western margin (Hammond et al., 2011; Bormann, 2013, 2016; Pierce et al., 2021). This deformation is accommodated by active transtensional faulting along the Dog Valley fault as well as a set of conjugate faults including the northwest-striking, right-lateral Polaris (e.g., Hunter et al., 2011) and Truckee faults. The system has generated several strong historical earthquakes (1966 M6.6 and two ~M6 earthquakes in 1914 and 1948), numerous smaller earthquakes (e.g.: 2021 M4.7), and poses a significant surface fault rupture and strong ground motion hazard for the communities of Truckee and Reno, as well as several water storage dams in the region. Previous assessments of the Dog Valley fault have been limited to seismic hazards evaluations related to dam safety (Olig et al., 2005; Hawkins et al., 1986). Olig et al. (2005) Summer 2021

Figure 1. Regional fault map. The Dog Valley fault is part of the Northern Walker Lane, an area of distributed dextral shear that accommodates ~5-7 mm/yr of northwest directed dextral shear, subparallel to the San Andreas fault. Faults (red) modified after USGS Quaternary Fault & Fold Database.

described tectonic geomorphic features along the fault including side-hill benches, ridge-crest saddles, aligned linear drainages, and reversals in scarp directions. Additionally, Olig et al. (2005) inferred a cumulative left-lateral displacement of 3.6-4.0 km since ~3 Ma. Several trenching efforts by Hawkins et al. (1986) did not expose the fault, however their trenches may have been located across scarps with adverse groundwater conditions and/or secondary cracks related to the 1966 earthquake. Despite this documented activity, the Dog Valley fault is not included in the US Geological Survey National Seismic Hazard model. Slip rate estimates for the Dog Valley fault are uncertain due to the lack of absolute age control for faulted surfaces, and paleoseismic parameters are non-existent. Thus, we initiated a study to better characterize this fault for seismic hazards applications.

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AEG2021 – ANNUAL MEETING PREVIEW PROFESSIONAL CONTRIBUTIONS the mouth of a small alluvial valley (Figure 4). An apparent left deflection of an ephemeral stream channel adjacent to the trench occurs along the strike of the fault.

Figure 2. Map of tectonic geomorphic features and fault traces along the Dog Valley and Polaris faults. Yellow stars indicate sites of previous studies.

Mapping Tectonic geomorphic features and fault traces were mapped along the length of the Dog Valley fault based on interpretation of lidar hillshade maps and field reconnaissance. Mapping along the Dog Valley fault indicates that it is characterized by rightstepping, en échelon fault strands expressed by subdued geomorphic features including oppositely facing scarps, closed depressions, aligned linear ridges, and sidehill benches (Figure 2). The lidar data reveal that the trace of the Dog Valley fault goes through the Stampede Dam, maintained by the US Bureau of Reclamation. Field observations indicate that strands of the Dog Valley fault offset Miocene andesite flow breccias and tuff breccias exposed in a roadcut immediately northeast of the dam (Figure 3). Thus, future fault rupture may pose potentially severe, and underappreciated seismic hazard for the downstream communities including Reno. A paleoseismic trench (DV1) was excavated approximately 3 km northeast of Stampede Reservoir where the fault forms a 2-m high northwest-facing scarp across Figure 4. UPPER: Photo of excavator at the toe of the fault scarp. LOWER: East wall of the trench showing sharp juxtaposition of fluvial units across an apparently dipping fault.

A New Trenching Methodology

Figure 3. Photo of faulted Miocene andesitic breccia and tuff in a roadcut adjacent to the east side of Stampede Dam. Holocene fault scarps are visible in lidar data in the hillside above this roadcut. 30

We were fortunate to have access to a small excavator, which remained on site for the duration of the project. After initially logging the first cut of the trench, we used the excavator to progressively peel back trench walls, ~20 cm at a time, creating both fault-parallel and fault-orthogonal slices. Each trench slice was scanned using a 2020 iPad Pro lidar scanner with the SiteScape app and photographed using overlapping photos from a Google Pixel2 smartphone camera. The photos were processed using Agisoft Metashape software to construct SfM models. The dense colored point clouds from the SfM models were then exported into CloudCompare software, which was used first to reference the lidar scans using flags in areas of the trench wall that did not change during progressive excavation as tie points (Figure 5, middle). Then, the SfM point clouds

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Figure 6. Plan view of CloudCompare scene showing the referenced point clouds of 10 of the 14 slices. Fault approximate location dashed in red.

Figure 5. Top: Photo of the 3D trench mid-excavation. Middle: Similarly oriented aligned lidar scans and higher resolution SfM point cloud (bottom) fitted to the lidar scans. The dotted white lines in the lower scene shows the channel margins that are left-laterally displaced ~80 cm by the fault (dashed red).

least one earthquake that broke the entire stratigraphic package. Radiocarbon analyses on five charcoal samples constrain the age of the earthquake to after ~8,100 cal yr. BP (samples and ages shown on trench log, Figure 7). Several upward fault terminations were observed lower in the stratigraphy however, the similarity of deposits and the flooded conditions at the base of the trench precluded confidently attributing these features to additional paleoseismic events. A fault-parallel slice of the trench (P2 in Figure 6) exposed a sand dike that nearly reached the surface, indicating limited post-faulting deposition and precluding dating any post-event deposit that could bracket the age of the event. The observed facies and thickness changes of stratigraphic units across the fault are consistent with strike-slip displacement. Thus, to assess the amount of lateral displacement in the most recent event, we expanded trench DV1 by cutting fourteen parallel and perpendicular slices of the wall to track a prominent channel margin. The 3D trench scene was used to reconstruct the offset channel margin. The model reconstruction confirmed field measurements indicating that the channel intersects the fault at a high angle and was left-laterally displaced during the most recent earthquake by ~80 cm (Figure 5).

were referenced to each of the corresponding lidar scans, again using flags or small stones in each of the lidar and SfM clouds as tie points (Figure 5, lower). The final result is a single high-resolution, spatially accurate 3D model of all 14 trench slices (Figure 6).

The Trench The trench exposed a sequence of low-energy saturated interbedded fluvial overbank sands with cobble lenses and peaty buried meadow soils (Units 3 and 4). These deposits are clearly juxtaposed against relatively higher-energy dry indurated fluvial coarse sandy silt and gravel channel deposits (Units 5 and 6) (Figure 7). A massive-to-weakly stratified brown-gray silt (Unit 2) and the modern soil (Unit 1) overlies these deposits. The stratigraphic relationships indicate the occurrence of at Summer 2021

Figure 7. Orthophotomosaic and stratigraphic log of the west wall of trench DV1 along the Dog Valley fault.

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Discussion/Conclusions Observations from trench DV1 along the Dog Valley fault indicate the occurrence of at least one earthquake that occurred after ~8,100 cal yr B.P., which was associated with ~0.8 m of left-lateral displacement. Comparing this result to previously reported earthquake timing data from the conjugate Polaris fault indicates that the most recent earthquake along both faults post-dates ~7-8 ka (Melody et al., 2012). Although broadly constrained, the earthquake history allows the possibility that ruptures along each fault occurred closely spaced in time or possibly contemporaneously. Conjugate ruptures have occurred in several historical earthquakes both globally and in the Walker Lane (e.g., 2019 Ridgecrest; 2015 Nine-Mile Ranch; 1986 Chalfant Valley) and suggests that this style of strain release may be an underappreciated seismic hazard in the Walker Lane.

Reitman, N.G., Bennett, S.E.K., Gold, R.D., Briggs, R.W., and DuRoss, C.B., 2015, High-resolution trench photomosaics from image-based modeling: Workflow and error analysis: Bulletin of the Seismological Society of America, 105, no. 5, 2354–2366. Westoby, M.J., Brasington, J., Glasser, N.F., Hambrey, M.J., Reynolds, J.M., 2012, ‘Structure-from-Motion’ photogrammetry: A low-cost, effective tool for geoscience applications: Geomorphology 179, 300–314. https://doi.org/10.1016/j.geomorph.2012.08.021.

About the Authors: Dr. Ian Pierce is a Postdoctoral Research Fellow at the Centre for the Observation and Modeling of Earthquakes Volcanoes and Tectonics at the University of Oxford, UK. Ian Pierce is supported by the Leverhulme Trust. He completed his PhD, entitled Active Faulting in the Central Walker Lane, in 2019.

Acknowledgements We are grateful for discussions in the field with T. Dawson, G. Seitz, J. Zachariasen, S. Wesnousky, J. Bormann, J. McNeil, K. Adams, and K. Knudsen, and assistance from R. Arrowsmith in reconstructing the trench model. Research supported by US Geological Survey (G20AP00055). Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the United States Government.

Dr. Rich Koehler is an Associate Professor of Geology at the Nevada Bureau of Mines and Geology and University of Nevada, Reno. He has worked closely with Dr. Pierce on several recent projects.

References Angster, S., Wesnousky, S.G., Huang, W., Kent, G., Nakata, T., and Goto, H., 2016, Application of UAV photography to refining the slip rate on the Pyramid Lake fault zone, Nevada: Bulletin of the Seismological Society of America, 106, no. 2, 785–798. Bormann, J., 2013, New insights into strain accumulation and release in the central and northern Walker Lane, Pacific–North American plate boundary, California and Nevada, USA: PhD Dissertation, Univ. of Nevada, Reno, Nevada. Bormann, J., Hammond, W.C., Kreemer, C., and Blewitt, G., 2016, Accommodation of missing shear strain in the central Walker Lane, western North America: Constraints from dense GPS measurements: Earth and Planetary Science Letters, 440, 169–177. Delano, J.E., Briggs, R.W., DuRoss, C.B., and Gold, R.D., 2021, Quick and dirty (and accurate) 3D paleoseismic trench models using coded scale bars: Seismological Research Letters, XX, 1–12. Hammond, W. C., Blewitt, G., and Kreemer C., 2011, Block modeling of crustal deformation of the northern Walker Lane and Basin and Range from GPS velocities: Journal of Geophysical Research, 116. Hawkins, F.F., LaForge, R., and Hanson, R.A., 1986, Seismotectonic study of the Truckee/Lake Tahoe area northeastern Sierra Nevada California for Stampede, Prosser Creek, Boca, and Lake Tahoe dams: U.S. Bureau of Reclamation Report no. 85-4. Hunter, L.E., Howle, J.J., Rose, R.S., and Bawden, G.W., 2011, Lidar-assisted identification of an active fault near Truckee, California: Bulletin of the Seismological Society of America, 101, 1162–1181. Melody, A.D., Whitney, B.B., and Slack, C.G., 2012, Late Pleistocene and Holocene faulting in the western Truckee Basin north of Truckee, California: Bulletin of the Seismological Society of America, 102, 2219–2224. Olig, S., Sawyer, T., Anderson, L., Wright, D., Wong, I., and Terra, F., 2005, Insights into Quaternary strain patterns in the northern Walker Lane from mapping and source characterization of faults near Truckee, California: Seismolological Research Letters, v. 75, p. 251. Pierce, I.K.D., Wesnousky, S.G., Owen, L.A., Bormann, J.M., Li, X., and Caffee, M., 2021, Accommodation of plate motion in an incipient strike-slip system: The central Walker Lane: Tectonics, 40, e2019TC005612. 32

CALL FOR PAPERS

AEG’s journal Environmental & Engineering Geoscience (E&EG) is currently seeking articles for review and possible publication.

E&EG is dedicated to publishing peerreviewed, high quality, original research and case studies on environmental geology, engineering geology, geotechnical engineering, geomorphology, low-temperature geochemistry, applied hydrogeology, and near-surface processes. Visit https://www.editorialmanager.com/eeg, the Peer Track on-line submission platform, for Instructions for Authors, the Style Guide, and to login. Published quarterly and hosted at GeoScienceWorld (http://eeg .geoscienceworld.org/), E&EG publishes articles ahead-of-issue, as soon as they are ready. Current and past issues are available to GSA members who select the journal as part of their annual dues and subscriptions options and to AEG members as a benefit of membership. For more information or to discuss possible special issue topics, please contact a co-editor: Abdul Shakoor (ashakoor@kent.edu) or Eric Peterson (ewpeter@ilstu.edu).

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e h t e v a S Dates…for These Future AEG Events AEG/USSD Workshop

AEG 2023 Annual Meeting

Westin Fort Lauderdale Beach Resort

Portland Marriott Downtown Waterfront – Portland, Oregon

December 6–8, 2021 This workshop will focus on Best Practices in Specialty Geotechnical Construction Techniques for Dam Exploration and Remediation. Information will be posted soon on www.aegmeetings.org.

AEG 2022 Annual Meeting Planet Hollywood Resort – Las Vegas, Nevada September 13–17 Your fun begins on The Strip, Las Vegas’ main artery and home to bustling casinos, worldclass restaurants, ornately designed resorts and over-the-top shows. Overlooking the Las Vegas Strip, our Annual Meeting hotel—Planet Hollywood Resort—is in the middle of everything you will want to experience. This Annual Meeting will be exciting, educational, and a great opportunity to reconnect with your colleagues and meet new ones.

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September 19–24 The In-Person AEG 2020 Annual Meeting has been rescheduled for 2023. Portland, Oregon’s largest city, sits on the Columbia and Willamette rivers, in the shadow of snow-capped Mount Hood. It’s known for its parks, bridges, and bicycle paths, as well as for its ecofriendliness and its microbreweries and coffeehouses. The city hosts thriving art, theater, and music scenes. Surrounded by Portland hot spots, the Marriott Portland Downtown Waterfront hotel reflects the vibrancy of the city and is located directly on the waterfront in downtown, surrounded by more than 60 breweries. Wind down with friends by sampling some of the 150 types of whiskey at their on-site restaurant, Proof Reader. The hotel even helps you go green with complimentary car-charging stations, biodegradable straws and easy access to light rail from the nearby Morrison Subway Station. At night, retire to elevated guest rooms with 24-hour room service, waterfall showers, free Wi-Fi, premium channels and views of Portland. Don’t miss all of the exciting Field Courses, Guest Tours and the Special Event at the Oswago Hills Vineyard planned for this incredible Annual Meeting.

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Paleoseismology in Wine Country: Paleoseismic Investigations along the Rodgers Creek Fault in Sonoma County, California Robert W. Givler, John Baldwin, and Christopher Bloszies

Introduction

he most recent Uniform California Earthquake Rupture Forecast (UCERF 3.0) (Field et al., 2015) assigns a probability of 32% that the HaywardRodgers Creek fault (HRCF) will produce an earthquake of M≥6.7 in the next 30 years, the highest probability for any San Francisco Bay Region fault other than the San Andreas fault (Figure 1). As compared to previous models, the UCERF 3.0 model also increased the number of multi-fault ruptures and doubled the probability of M>7.2 events (Field et al., 2015). The age of the most recent event (MRE) and earthquake recurrence are important parameters (especially for time-dependent models like UCERF 3.0) for developing rupture scenarios, as well as computing probabilities of future major earthquakes along the HRCF. Paleoseismic data currently considered in the UCERF 3.0 model for the Rodgers Creek fault (RCF) are sparse and based primarily on two sites along the central part of the RCF (Figure 1; Budding et al., 1991; Schwartz et al., 1992; Hecker et al., 2005). Our recent research conducted at two sites located along the southern RCF in Sonoma County, California—Tolay Marsh (Rams Gate Winery) and Cline Vineyard Sites—focused on obtaining paleoseismic data to improve existing forecasting models.

Rodgers Creek Fault The RCF represents the central part of a 275-km-long fault system that includes the Hayward, Rodgers Creek-Healdsburg, and Maacama faults (Figure 1; McLaughlin et al., 2012). The 60-km-long RCF has a late Holocene dextral slip rate of 6.4 to 10.4 mm/yr (Budding et al., 1991; Schwartz et al., 1992; Hecker et al., 2005; Blisniuk and Walker, 2018). The central and southern sections of the RCF are divided by a possible 1km-wide step over, and the southern section is separated from the Hayward fault across a 4-km-wide right bend through San Pablo Bay (Figure 1; Watt et al., 2016). The RCF has had several historic moderate-sized earthquakes including the 1969 M5.6 and M5.7 earthquakes near Santa Rosa (Wong, 1991), and the poorly located 1898 M6.2 to M6.7 Mare Island events (Figure 2; Toppozada et al., 1992). Figure 1. Southern Rodgers Creek fault (primary strands shown in red from Hecker et al., 2018) and paleoseismic sites along the fault (Buntz et al. 1991; Schwartz et al., 1992; Randolph-Loar, 2002; 2003; Hecker et al., 2005; Givler et al., 2010; 2016; 2018). Blue dashed line presents the historical margin of tidal marsh. Black lines are other Quaternary faults.

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Figure 2. Tolay Marsh site geologic map (Witter et al., 2006) illustrating the location of the USGS seismic line collected as part of this study and gouge core transects #1-3. Holocene and Late Quaternary faults shown in red and orange. Suspected Holocene faults shown as thin green lines. Blue line represents the historic limit of tidal marshes. Geologic units include artificial fill (af), Quaternary Holocene fan (Qhf), Quaternary Holocene channel (Qhc), Quaternary Holocene terrace (Qht), Quaternary Holocene Bay mud (Qhbm), and bedrock (br).

Active aseismic creep has been well documented both south and north of the RCF, along the Hayward and the Maacama faults, respectively (Figure 1). Recent studies also document creep along the RCF, at an approximate rate of 1.5±0.3 mm/yr (Lienkaemper et al., 2014; McFarland et al., 2016). Data from geodetic measurements and from PS-InSAR datasets indicate a faster creep rate up to or >6 mm/yr, near Santa Rosa (Floyd, et al., 2009; Funning et al., 2007). The lowest measured rate of creep of 0.3±0.5 mm/yr is along the southern RCF, located 3.6 km to the south of the Cline Vineyard site (site RCWD in McFarland et al., 2016). Dynamic rupture modeling of the HRCF suggests that earthquakes may nucleate on locked parts of the fault (e.g., the southern RCF) and rupture through creeping strands (e.g., southern Hayward fault) leading to M7+ earthquakes (Harris et al., 2021).

Existing RCF Paleoseismic Data Four previous paleoseismic investigations on the RCF provide the basis for the late Holocene event chronology for the central and southern sections of the RCF (Figure 2; Budding et. al, 1991; Schwartz et. al, 1992; Randolph-Loar, 2002; RandolphLoar et al., 2004; Hecker et al., 2005). Collectively, these studies yield an average earthquake recurrence interval of 131–370 years (Budding et. al, 1991; Schwartz et. al, 1992; Hecker et al., 2005). The findings of these studies are summarized below:

Triangle G Ranch and Beebe Ranch Sites on the central RCF (Figure 1)—Schwartz et al. (1992) interpret two events at the Triangle G Ranch: (1) an oldest event that occurred shortly Summer 2021

before 993 to 1193 AD (962–762 yr BP), and (2) a younger event that occurred after 993-1193 AD (962–762 yr BP) but before 1275–1413 AD (680 to 542 yr BP). Using the occurrence of non-native pollen and review of historical records, Hecker et al. (2005) constrain the timing of the MRE at this site to after A.D. 1715 and probably before A.D. 1776. Hecker et al. (2005) estimate the MRE right-laterally offset a buried paleochannel a minimum of 2.2 m (+1.2, -0.8). They also compare the timing of the RCF MRE to the timing of the last prehistoric ruptures on the Hayward fault (A.D. 1640–1776; 315–234 yr BP), to support an interpretation of a possible linked rupture of both faults across San Pablo Bay.

Martinelli Ranch Site on the southern RCF (Figure 1)—RandolphLoar et al. (2004) performed a paleoseismic study at Martinelli Ranch that constrained a single surface rupturing between 1.0– 0.79 ka and 10.7–9.6 ka. Donnell Ranch Site on the southern RCF (Figure 1)—Located on the central portion of the southern RCF, Randolph-Loar (2002) identified one event prior to 6.8 ka, two events between 6.8 and 3.7 ka, and three post 3.7 ka.

Tolay Marsh Site (Rams Gate Winery) The Tolay Marsh site is located at the intersection of the southern RCF and the northern edge of San Pablo Bay (Figures 1 and 2). This site is situated along the San Pablo Bay in an area relatively undisturbed, and currently is isolated from the bay by narrow levees bordering slack-water sloughs that meander across the estuary and flow south to the bay. At the Tolay Marsh site, we:

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Figure 3. Tolay Marsh seismic reflection profile (uninterpreted and interpreted on the left and right, respectively) (Givler et al., 2010). Topographic profile at the top of the lines illustrates the width of the fault zone with respect to topography. No vertical exaggeration in seismic line. Red lines are interpreted faults. Colors on interpreted line are increasing P-wave velocity. See Figure 2 for seismic line location.

(1) collected and interpreted seismic reflection data across the fault in collaboration with the US Geological Survey (USGS) (Figure 3); and (2) collected cores of shallow estuarine stratigraphy. We then used radiocarbon dating and diatom analyses to confirm the timing and evidence of rapid co-seismic submergence (Knudsen et al., 2002). Diatom analyses were completed by Eileen Hemphill-Halley (Humbolt State University). At the interface with the marsh, the site is bounded by a northwest-southeast trending Tertiary volcanic ridge cut by multiple Holocene and Quaternary active fault strands (Figure 2; Wagner et al., 2011). The alignment of the fault strands with southwest-and northeast-facing fault scarps, linear channels, closed depressions, springs, and bedrock topographic highs suggest structural complexity and long-term deformation (Hart, 1992; Randolph-Loar et a1., 2004). Previous trenches at the site provide further documentation on differentiating Holocene strands from older Quaternary strands. Based on our seismic reflection profile across the fault, we interpret that the fault forms a broad, approximately 500- to 600-m-wide bedrock pop-up structure intersected by multiple shallow faults (Figure 3). Some of the faults imaged in the seismic line coincide with Quaternary and Holocene fault traces mapped at the ground surface (Givler et al., 2010). Unfortunately, the presence of the flood control levees to the south along strike prevented gouge core transects where the fault projects into the marsh (Figure 2). 36

Shallow gouge and vibratory cores data, performed in transects parallel to the USGS seismic line, were used to provide stratigraphic context and age control on the deformation across the primary fault strand(s) (Figure 4). Stratigraphic and paleontologic analyses of gouge and vibracore samples document a sequence of late Pleistocene to Holocene alluvial and late Holocene marsh sediments, such as marsh soils (peaty muds), quiet water deposits (mud), and algal mat-rich horizons overlying Pleistocene(?) coarse-grained overbank alluvium (Figure 4). On the northeastern side of the RCF and along gouge transects #1 and #2, the marsh stratigraphy shallows toward the ground surface and defines a northeast-facing subsurface escarpment coincident with present-day topography and pop-up structure (Figures 2 and 4). Distinct elevation differences between closely spaced gouge cores also allow for the interpretation of possible southwest-side-up displacement of late Holocene strata (Unit 2d in Figure 4). This interpretation is supported by present-day tectonic geomorphology (Figure 2), geophysically imaged subsurface offsets (Figure 3), and trench data to the northwest (see below). Based on the correlations between paleoecological (diatom) stratigraphic data, at least one coseismically-related submergence event occurred at the site in the vicinity of the gouge core transects. Diatom and radiometric analyses of a buried peaty mud horizon (Unit 2d) indicate a rapid co-seismic submergence event that abruptly changed the diatom paleoecological

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Figure 4. Gouge and vibracore transect #2 illustrating the shallow marsh stratigraphy along the northeast margin of Tolay marsh. Stratigraphic relationships and paleontological diatom analyses of fossils preserved in these buried deposits from viabracore VC2 indicate possible rapid coseismic submergence between Units 2d and 2e, which we tentatively correlate with a possible offset of unit 2d between GC29 and GC20 (Givler et al., 2010).

conditions after 2150–2350 cal yr BP and before 1900–2300 cal yr BP (Figure 4). Utilizing Bayesian models, we constrain the timing of this event between 2100 and 2300 yr BP (B.C. 346 and 152) at the 95.4% confidence limit. Following criteria defined in Knudsen et al. (2002), we interpret this as evidence of a large earthquake on the RCF.

Cline Vineyards The Cline Vineyards site is located 1.3 km south of Highway 116 (Figure 1) on a Holocene fluvial terrace where the southern RCF juxtaposes two members of the Tertiary Sonoma Volcanics (Figure 5; Wagner et. al., 2002a; 2002b; Wagner et al., 2011). Near the Cline Vineyards site, fault traces associated with the RCF are defined by prominent tectonic-related geomorphology: northwest-trending topographic scarps, shutter ridges, deflected drainages, sag ponds, and aligned springs (Figure 3) (Hart, 1992; Randolph et al., 2004; Givler et al., 2019; Hecker et al., 2018). The results of our site surficial geologic mapping and subsequent paleoseismic trenching suggest the Cline Vineyards site is traversed by two RCF strands, an eastern and a western fault strand that displace late Holocene age fluvial terrace deposits (Qt1 and Qt2). Trench exposures (Figures 6 and 7) and 14C data confirm the Qt1 terrace surface is composed of early to late Holocene fluvial deposits separated by as many

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as five different buried soils, with the latest deposition on the Qt1 surface occurring after 680–760 cal yr B.P. (Unit 600). The multiple trenches excavated at the site provide direct evidence for late Holocene deformation that includes a combination of co-seismic folding and faulting distributed across the eastern and western strands (Figure 5). Event timing at the Cline Vineyard site includes the following: (1) Event E1 occurred after A.D. 1220-1280 (670– 740 cal yr BP) based on findings of trenches T-3 and T-2; (2) Events E2 and E3 occurred before A.D. 1040–1160 (800– 910 cal yr BP) from Trench T-3; (3) Event E4 faulted gravels in trenches T-5, T-7, and T-8 sometime after approximately B.C. 1050 (3000 cal yr BP)—this event may correlate with events E1, E2, or E3 based on the limited deposition on the Qt1 surface in the late Holocene; and (4) several earlier events older than B.C. 2050 (4000 cal yr BP) are inferred based on the available data in trenches T-5, T-7 and T-8, but these events remain poorly constrained.

Rogers Creek Fault Event Correlation To potentially correlate paleoseismic events interpreted at our two sites with past studies, we developed earthquake-timing information at the 95.4% confidence limit using Bayesian modeling software (OxCal - Bronk Ramsey, 2009; Figure 8).

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Figure 5. Map of the Cline Vineyard Site illustrating locations of paleoseismic trenches and key geologic units at the site. Abbreviations: Qt1 and Qt2Quaternary terrace 1 and 2, Qfh – Quaternary Holocene fan, Qc – Quaternary colluvium, Tsv-Tertiary Sonoma Volcanics (shown in grey). The western strand of the RCF is mapped along exposures within the drainage trending northwest and crossed by trenches T-2, T-3, T-4, T-5a, and T-6 before stepping to the right to the eastern strand intersected by trenches T-1, T-5b, T-2 and T-8. Figure 6. Photomosaic (above) and interpreted log (below) of the north wall of trench T-3. Key units include Sonoma Volcanics bedrock (Unit 10), Holocene fluvial deposits (Units 110 to 500), Holocene colluvium (Unit 150 and 350), late Holocene fluvial gravel (Unit 550) and Units 600/700 represent the most recent soils and overbank deposits. See Givler et al. (2019) for detailed unit descriptions.

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Figure 7. Interpreted log of the north wall of trench T-2. Key units include Sonoma Volcanics bedrock (Unit 1), Highly weathered bedrock (Unit 2), colluvium (Units 4, 5, 6, 11, and 12), Holocene fluvial deposits (Units 7, 8, 9, 10), Holocene colluvium (Unit 150 and 350), late Holocene fluvial gravel. See Givler et al. (2016) for detailed unit descriptions. Blue line represents the interpreted event horizon for the MRE (E1).

Figure 8. Summary of earthquake-timing data for the Cline and Tolay Marsh Sites. Earthquake PDFs generated using OxCal Bayesian modeling software (Bronk Ramsey, 2009). Alternative model for the Cline Site E1 is shown as a dotted line. Triangle G earthquake-timing data (Schwartz et al., 1992; Hecker et al. 2005) shown at the top of the figure for events E1, E2, and E3.

Although the constraints on event timing are broad at the Cline Vineyard and Tolay Marsh sites, the events correlate with other paleoseismic events identified on the RCF to the north at the Triangle G Site (Figure 1). For example, the timing of Cline Vineyard E1 (after A.D. 1220–1280) is broadly consistent with the Triangle G E1 (A.D. 1715–1776) identified by Hecker et al.

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(2005). Alternatively, it is possible the youngest faulting predates the surface soil in Cline Vineyard trench T-3 (Unit 600 in Figure 6;) which places the MRE between A.D. 1080 and 1260 (95.4% confidence). In the alternative interpretation, the MRE (E1) and Event E2 at the Cline Vineyard Site occurred before A.D. 1040–1160, which overlaps with the penultimate event

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HEADER HERE CONTRIBUTIONS PROFESSIONAL (E2) (A.D. 990–1410) at Triangle G Ranch (Hecker et al., 2005). Tolay Marsh Event E1 timing (B.C. 346–152, 95.4% confidence interval) also overlaps broadly with the timing constraints for the Cline Vineyard E2 and Triangle G E3 (before A.D. 900). Thus, our results generally support co-seismic surface rupture of the southern RCF with the RCF to the north (although these events can also be interpreted as separate events). This event chronology also overlaps with the northern Hayward fault to the south (Hecker et al., 2005) and supports the interpretation of co-seismic ruptures across San Pablo Bay between the two faults (Figure 1; Watt et al., 2016). These joint rupture scenarios are supported by dynamic rupture modeling (Harris et al., 2021), which favors nucleation on the “locked” southern RCF and propagation onto creeping sections of the Hayward fault to the south in larger events (M7+).

Summary Herein we summarize paleoseismic research at two separate sites along the southern RCF (Figure 1). The available paleoseismic data from previous studies and this research indicate that only two to three events have occurred along the fault in the last approximately one to two thousand years (Figure 7). It is unclear if this paucity of earthquake timing information is due to the apparent poor preservation of paleo-earthquakes, due to erosion (removal of evidence), or very low deposition for the sites currently evaluated, or from the overall fault behavior for the RCF. By comparison, the northern Hayward fault has a much more robust earthquake chronology with as many as nine events occurring between ~B.C. 400 and A.D. 1800 (HPEG, 1999). If there is a connectivity between the faults (e.g., Watt et al., 2016), it is possible that the RCF ruptures less frequently than the Hayward fault to the south, or more likely the existing late Holocene record on the RCF is very incomplete. More work is required at high-sedimentation sites to further constrain event timing and recurrence intervals along the RCF. For additional details regarding this research see Givler et al. (2010; 2019).

Acknowledgements Thanks to our many co-authors and collaborators (Michael Rymer; Rufus Catchings, Robert Sickler, Keith Knudsen, Nora Lewandowski, Eileen Hemphill-Halley, Josh Goodman, and Matt Huebner) and the landowners of the Tolay Marsh and Cline Vineyard sites.

References Blisniuk, K., and Walker, A., 2018, Determining the distribution of slip across the northern San Andreas fault system: through long-term fault slip rates: US Geological Survey NEHRP Final Technical Report Grant number. Budding, K.E., Schwartz, D.P., and Oppenheimer, D.H., 1991, Slip rate, earthquake recurrence, and seismogenic potential of the Rodgers Creek fault zone, northern California: Initial results: Geophysical Research Letters, v. 18, no. 3, p. 447–450. Field, E.H., Biasi, G.P., Bird, P., Dawson, T.E., Felzer, K.R., Jackson, D.D., Johnson, K.M., Jordan T.H., Madden, C., Michael, A.J., Milner, K.R., Page, M.T., Parsons, T., Powers, P.M., Shaw, B.E., Thatcher, W.R., Weldon, R.J., Seng, Y., 2015, Long-term time-dependent probabilities for the Third Uniform California Earthquake Rupture Forecast (UCERF3), Bulletin of the Seismological Society of America, v. 105, no. 2a, p. 511–543.

Floyd, M .A., Funning, G .J., Lipovsky, B ., 2009, Geodetic evidence for creep along the Rodgers Creek and Maacama fault zones, northern California: AGU Fall Meeting, abstract #G23B-0692. Funning, G.J., Burgmann, R., Ferretti, A., Novali, F., Fumagalli, A., 2007, Creep on the Rodgers Creek fault, northern San Francisco Area from a 10-year PS-InSAR dataset: Geophysical Research Letters, v. 34, L19306, doi:10.1029/2007GL030836 Givler, R.W., Baldwin, J., Knudsen, K., 2010, Structural characterization and pilot paleoseismic investigation of the southernmost Rodgers Creek fault, northern San Pablo Bay, California: Final Technical Report for USGS NEHRP Award No. G09AP00022. Givler, R.W., and Baldwin, J., 2016, Pilot paleoseismic investigation of the southernmost Rodgers Creek fault, northern San Pablo Bay, California: Final Technical Report for USGS NEHRP Award No. G13AP00036. Givler, R.W., Baldwin, J.N., Bloszies, C., 2019, Paleoseismic investigation of the southernmost Rodgers Creek fault at Cline Vineyards Site, Sonoma, California: Final Technical Report for USGS NEHRP Award No. G17AP00102. Harris, R. A., Barall, M., Lockner, D. A., Moore, D. E., Ponce, D. A., Graymer, R.W., et al., 2021, A geology and geodesy based model of dynamic earthquake rupture on the Rodgers Creek-Hayward- Calaveras fault system, California: Journal of Geophysical Research: Solid Earth, 126, e2020JB020577. https://doi.org/10.1029/2020JB020577. Hayward fault Paleoearthquake Group (HFPG), 1999, Timing of paleoearthquakes on the Northern Hayward fault—preliminary evidence in El Cerrito, California: US Geological Survey Open-File Report 99–318. Hecker, S., and Randolph Loar, C.E., 2018, Map of recently active traces of the Rodgers Creek fault, Sonoma County, California: US Geological Survey Investigations Map 3410, 7 p., 1 sheet, https://doi.org/10.3133/sim3410. Hecker, S., Pantosti, D.P., Schwartz, D.P., Hamilton, J.C., Reidy, L.M., Powers, T.J., 2005, The most recent large earthquake on the Rodgers Creek fault, San Francisco Bay area: Bulletin of the Seismological Society of America, Vol. 95, No. 3, pp. 844–860, June 2005. Knudsen, K. L., R. C. Witter, C. E. Garrison-Laney, J. N. Baldwin, G. A. Carver, L.B. Grant, and W.R. Lettis, 2002, Past earthquake-induced rapid subsidence along the northern San Andreas fault: a paleoseismological method for investigating strike-slip faults: Bulletin of the Seismological Society of America, V. 92, No. 7, pp. 2612-2636. Lienkaemper, J.J., McFarland, F.S., Simpson, R.W., Caskey, S.J., 2014, Using surface creep rate to infer fraction locked for sections of the San Andreas fault system in northern California from alignment array and GPS data: Bulletin of the Seismological Society of America, V. 104, no. 6, p. 1–21. McFarland, F. S., Lienkaemper, J.J., Caskey, S .J., Grove, K., 2016, Data from theodolite measurements of creep rates on the San Francisco Bay region faults, California: 1979 -2007, US Geological Survey Open-file report 20071367, 14 p. (updated version 1.8 March 2016). McLaughlin, R.J., Sarna-Wojcicki, A.M., Wagner, D.L., Fleck, R.J., Langenheim, V.E., Jachens, R.C., Clahan, K., Allen, J. R., 2012, Evolution of the Rodgers Creek–Maacama right-lateral fault system and associated basins east of the northward-migrating Mendocino Triple Junction, northern California: Geosphere, v. 8; no. 2; p. 1-32. Randolph-Loar, C.E., 2002, Neotectonics of the southern Rodgers Creek fault, Sonoma County, California: Masters Thesis, San Francisco State University, 154 p. Randolph-Loar, C. E., Witter, R. C., and Lettis, W. R., 2004, Paleoseismic investigation of the southern Rodgers Creek fault, Martinelli Ranch, Sonoma County, CA: Final Technical Report for the US Geological National Earthquake Hazards Program, 14 p. Schwartz, D.P., Lienkaemper, J.J., Hecker, S., Kelson, K.I., Fumal, T.E., Baldwin, J.N., Seitz, G.G., Niemi, T.M., 2014, The earthquake cycle in the San Francisco Bay region: A.D. 1600-2012: Bulletin of the Seismological Society of America, v., 104, no. 3, p. 1-30. Schwartz, D.P., Pantosti, D., Hecker, S., Okumura, K., Budding, K.E., and Powers, T., 1992, Late Holocene behavior and seismogenic potential of the Rodgers Creek fault zone, Sonoma County, California: Borchardt, G., et al., eds., Proceedings of the Second Conference on Earthquake Hazards in the Eastern San Francisco Bay Area: California Division of Mines and Geology Special Publication 113, p. 393-398.

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PROFESSIONAL CONTRIBUTIONS HEADER HERE Toppozada, T.R., Bennett, J.H., Hallstrom, C.L., and Youngs, L.G., 1992, 1898 “Mare Island” earthquake at the southern end of the Rodgers Creek fault: Borchardt, G., et al., Proceedings of the Second Conference on Earthquake Hazards in the Eastern San Francisco Bay Area: California Division of Mines and Geology Special Publication 113, p. 385-392. Wagner, D.L., Saucedo, G.J., Clahan, K.B., Fleck, R.J., Langenheim, V.E., McLaughlin, R.J., Sarna-Wojcicki, A.M., Allen, J.R., Deino, A.L., 2011, Geology, geochronology, and paleogeography of the southern Sonoma volcanic field and adjacent areas, northern San Francisco Bay region, California: Geosphere, v. 7, no 3, p. 658-683. Watt, J., Ponce, D., Parsons, T., Hart, P., 2016, Missing link between the Hayward and Rodgers Creek faults: Science Advances, V. 2, e1601441. Wong, I.G., 1991, Contemporary seismicity, active faulting and seismic hazards of the Coast Ranges between San Francisco Bay and Healdsburg, California: Journal of Geophysical Research, v. 96, no. B12, p.19, 891-19,904.

About the Authors Robert Givler is a certified engineering geologist (CEG) at Lettis Consultants International, Inc. with over 20 years of professional experience conducting geologic and geotechnical investigations focused on geologic hazard evaluations throughout the California and the United States. He has recently completed paleoseismic studies on the Rodgers Creek Fault (described herein) and the Pajarito Fault System in northern New Mexico. John Baldwin is a CEG at Lettis Consultants International, Inc. with over 25 years of experience in conducting seismic hazard assessments and performing paleoseismic research in the United States and internationally. He currently is conducting

L to R: Authors Chris Blozies, Robert Givler, and John Baldwin

earthquake-related research on the San Andreas and Quien Sabe faults in northern California. Chris Bloszies is a Quaternary geomorphologist at Lettis Consultants International, Inc. with over nine years of experience in surficial geologic mapping and paleoseismic investigation. His interests lie in understanding how tectonic and/or climatological perturbations influence landscape evolution, hydrologic systems, and soil formation. His recent earthquake-related research includes faults in Northern California, the New Madrid Seismic Zone, and Taiwan, and paleoclimate studies in East Africa and in mid-continental United States.

The workshop is co-sponsored by AEG and USSD and will be two days of presentations followed by an optional field trip to Herbert Hoover Dike. Presentations will cover geotechnical investigations and dam modifications best practices and risk management, followed by a round table discussion with all the speakers.

The goals of the Workshop are to: l Highlight best practices in geotechnical exploration and construction in dams and levees l Present case histories with a range of exploration and construction techniques l Discuss issue resolution and decision making in a risk framework

Registration is limited to the ﬁrst 100 people, so sign up now! www.aegmeetings.org Summer 2021

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The 1811–12 New Madrid Earthquakes – The Backstory Phyllis Steckel

eginning on December 16, 1811 and continuing through February 1812, at least four large earthquakes occurred in what is now northeast Arkansas and southeast Missouri. Each of these four large earthquakes has since been estimated to have been about magnitude 7½ or larger. They occurred on December 16, 1811; and January 23, February 7, and February 23, 1812. Many strong aftershocks continued for months, finally tapering off after several years. The New Madrid (MAD-rid—accent on the first syllable) fault system has since been recognized as a complex, buried fault zone that has been intermittently active for millions of years. But the risk it poses today to the people, property, infrastructure, and economy that has been added to the region since the early 1800s is difficult to understand and mitigate.

ILLINOIS BASIN

St. Francois Mountains

OZARK PLATEAU

The Regional Setting

To the northwest of New Madrid are the St. Francois Mountains and the Ozark Plateau (Figure 1). In the St. Francois Mountains region, Precambrian basement rocks are locally exposed at the surface, while Paleozoic strata underlie the surrounding regions of the Ozark Plateau physiographic province. The southern part of the Illinois Basin is located northeast of New Madrid. The Mississippi River and its floodplain flow from the north, a rough boundary between the Ozark Plateau to the west and the Illinois Basin to the east. The river empties into the Mississippi Embayment, a bedrock trough that deepens and widens from the northeast to the southwest. From about the junction of the Mississippi and Ohio rivers and to the south-southwest for about 300 miles (380 km), the axis of the Mississippi Embayment is roughly parallel with today’s Mississippi River. Over the last tens of millions of years, the Mississippi Embayment has filled with sediment. Most of this sediment was scraped off the northern and central parts of the North American continent by many glacial pulses, transported, and neatly sorted by the Mississippi River and its Missouri and Ohio tributaries system. Reworked glacial and alluvial material carried south by these rivers has built up the surface of the Mississippi Alluvial Plain section of the Gulf Coastal Plain. Glacial sediments from many hundreds of miles to the north were deposited into the Mississippi Embayment, creating a nearly-flat topography all the way to the Gulf of Mexico. These layers of sediments, several thousands of feet thick, amplify and prolong ground-shaking and expand the area affected by New Madrid earthquakes. Compared to earthquakes of similar magnitude in California, a New Madrid earthquake will affect four to six times as much area. 42

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Figure 1. Today, the New Madrid Seismic Zone includes southeast Missouri, northeast Arkansas, southern Illinois, and westernmost Kentucky and Tennessee. It includes three main faults, all of which probably were displaced during the 1811–12 series of earthquakes. Today, this epicentral area includes the second-largest steel production county in the US, one of the last aluminum smelters in the US, a major electric-power plant, the largest single consumer of electricity in Missouri, critical petroleum and natural gas pipelines that supply the northeastern US, the critical infrastructure of river-barge traffic on the Mississippi and Ohio rivers, and engineered drainage systems that are especially vulnerable to earthquake hazards. Other vulnerable industries include warehousing and overnight shipping in Memphis and Louisville, critical river port facilities, commodity transportation and storage, and multi-modal (rail, barge, and truck) hubs. FIGURE FROM USGS.

The Local Setting In the early 1800s, much of the northern part of the Mississippi Embayment was swampland at the surface. Flooding could occur at any time of year, fed by runoff from the Mississippi, Missouri, and Ohio river watersheds—nearly half of today’s continental United States. The entire Mississippi Embayment was thickly forested and essentially impenetrable for wagons and livestock at that time. As a result, keelboats, flatboats, rafts, and canoes were transportation necessities. The few settlements that were established were on the banks of the Mississippi River. It was the interstate highway of the 1800s. The town of New Madrid, established in 1789, is located within the Mississippi Embayment, on a sliver of slightly higher

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Figure 2. Instrumentally located seismicity 1974 to June 2021 (source CERI online catalog) highlights the active part of the New Madrid Seismic Zone (black oval). FIGURE FROM MITCHELL M WITHERS, CENTER FOR EARTHQUAKE RESEARCH AND INFORMATION (CERI), UNIVERSITY OF MEMPHIS.

ground. This sliver is the southernmost part of the Sikeston Ridge, the “crest” of which is only about 20-feet above the normal level of the Mississippi River. In those days, the Mississippi River level varied widely from raging flood to nearly dry, depending on weather and other conditions upstream. Thick forests, which were sometimes flooded and usually wet, surrounded the townsite. Clearings were limited to the townsite and small garden plots tended by the various households. Trees were plentiful, and logs from local clearing provided construction material.

The Town of New Madrid, Louisiana Territory, in 1811 In 1811, the town of New Madrid was a loose community of about 1,000 people. Great Britain, France, Spain, and the fledgling United States all had laid claim to the area at various times within the previous 20 years or so. The United States had just Summer 2021

purchased the Louisiana Territory from France in 1803. Before then, previous governments were allegiant to England, and even earlier, to Spain. (The State of Missouri would not exist for another nine years or so.) In the early 1800s, the residents of New Madrid reflected that diversity. Depending on who was speaking, local conversations were in French, Spanish, English, native languages, or a muddle of two or more of these. The government du jour, political allegiance, and administrative authority were much less of a concern to New Madrid residents than an outbreak of illness, a serious broken bone, or a bear in the garden. Life was difficult, the location was remote, resources were limited. Life-or-death challenges occurred almost daily. Government and impractical rules were just not all that important to the locals. Even so, New Madrid was an important and busy place. At that time, it was the largest and most important settlement along the Mississippi River between St. Louis and New Orleans. Memphis would not even be founded for another eight or ten

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HEADER HERE CONTRIBUTIONS PROFESSIONAL years. Cape Girardeau and Ste. Genevieve (now both in Missouri) were neither as large nor as important at that time. River traffic stopped in New Madrid to rest their crews, make repairs to their vessels, get news of river conditions ahead, deliver mail and months-old newspapers, and resupply provisions. Several known persons were in New Madrid at the time the earthquakes began on December 16, 1811. Eliza Bryan was about 31 years old and ran a boarding house or public lodging in New Madrid. To date, no record has been found of Eliza’s husband, so she probably was a widow. Her son, Fred Bryan, was about six years old. A newcomer to New Madrid was William Bratton, a veteran of Lewis and Clark’s Corps of Discovery venture in 1804–06. He had made the overland trek from St. Louis to the Pacific Ocean and back.

The Earthquakes Sometime around 2:00 am on the morning of December 16, 1811, a large earthquake occurred on the New Madrid fault system. Neither the exact time nor the epicenter location is known. In the New Madrid area, the weather was unseasonably warm, muggy, and still: it might have been in the 40s or maybe even the low 50s (degrees Fahrenheit). The shaking was intense and long-lasting, causing significant damage or destroying every structure and household in New Madrid. An acrid sulfur smell was released into the air—probably from decaying organics that were disturbed in the surrounding swamplands. In the area of New Madrid and much of the Mississippi Embayment, fountains of sandy water—sand blows or liquefaction features—spurted up from beneath the ground surface. Some continued to build up for hours to days after the main ground shaking stopped. These sand blows actively built up the immediate area around each vent with a deposit of fresh sand a few inches to a few feet thick. Linear crevasses opened in places that, before the earthquake, had been a flat and continuous surface. The banks of the Mississippi River had slumped into the channel from both sides of the river, dragging large trees and other debris with it. At least one person died in New Madrid, a probable heart attack. But dozens to perhaps hundreds more were probably lost; river travelers would simply disappear, and those of African and Native American ancestry were specifically not accounted. One of the most puzzling effects of the earthquake at New Madrid was that the Mississippi River quickly ran dry. The flow of water in the river stopped and completely drained the channel area. This interruption of the river lasted only a short time—perhaps only a few hours or so. Then it slowly recovered its murky flow and again began to drain along its previous course. This phenomenon has become an urban myth and has been repeated incorrectly as the “river ran backwards.” (Incorrect, but hard to remove from urban legend.) This was probably from Eliza Bryan’s description of “…the current of which [the Mississippi River] ran retrograde….” In reality, a surface fault rupture running nearly north-south was located just east and south of New Madrid. The west side of this surface rupture was uplifted, perhaps 30 to 50 feet. As a result, the course of the Mississippi River here—a distinct loop in the river known as “Kentucky Bend”—had been bisected 44

by the river. This created a natural dam made of the loose sediments of the river’s natural levee. This natural dam briefly interrupted the river’s flow, causing water from upstream to divert to the southeast and pond in an area now known as Reelfoot Lake. Because the uplifted material was easily eroded, the river soon cut through the soft mud and quickly returned to its former channel. The New Madrid earthquakes were felt in southern Canada, Massachusetts, South Carolina, and Georgia. Several of the larger earthquakes were felt in the White House in Washington DC by then-President James Madison. Literally thousands of aftershocks were recorded in Louisville, Kentucky by Dr. Jared Brooks. Historians have gleaned felt-reports from newspapers, personal journals, insurance logs, and many other sources. It was felt strongly at Fort Osage (near present-day Kansas City); in Savannah, Georgia; Charleston, South Carolina; and many towns along the Ohio and Lower Mississippi valleys. Felt-reports from the west and southwest have not yet been found. Very few literate English- or French-speakers lived in the region at that time, except for a few French-speaking Jesuit missionaries and Spanish-speaking traders traveling the Santa Fe Trail. In 1811, Abraham Lincoln was almost three years old, and he and his family lived only about 200 miles from New Madrid. They most certainly felt the earthquakes, but specific information on the impact to their household has not yet been found. A few months later, the Territorial Governor William Clark, who, with Meriwether Lewis, had led the Corps of Discovery to the Pacific Ocean and back in 1804-1806, led a successful effort to have Congress pass “A Resolution for the Relief of the Inhabitants of the County of New Madrid”—the first federal disaster funding bill. The New Madrid earthquake series was just that: a series of earthquakes. At least four earthquakes of about magnitude 7½ occurred in a little over two months. The ground-shaking, liquefaction, surface fault rupture, and landslides would repeat after each large event. Aftershocks began immediately and continued incessantly for many months. New Madrid was destroyed, and almost all residents left the area as soon as possible. Travel on the Mississippi River was difficult to impossible.

After the Earthquakes Several years later, the Reverend Lorenzo Dow, urged Eliza Bryan to write a descriptive account of what she saw and experienced during that time. In 1816, Eliza Bryan, a gifted writer, had completed her letter to Lorenzo Dow www.memphis.edu/ceri/compendium/pdfs/bryan.pdf A quick look at Eliza Bryan’s account suggests that she was wildly imaginative, if not fantastical, with her descriptions. However, a closer review of her writing proves her observations to be amazingly accurate. Numerous still-visible earthquake scars in the New Madrid region verify Eliza’s various descriptions that were written more than 200 years ago. Other plausible and proven geologic and physical explanations support her observations. Eliza Bryan was a gifted writer and keen observer. Without her meticulous account, the New Madrid story would not be what it is today.

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Earthquake Insight Field Trip Since 2005, the annual Earthquake Insight Field Trip has traveled a route along the Mississippi River from the St. Louis area, south into the Mississippi Embayment. Stops are made at historical sites that tell the story of the 18111812 New Madrid earthquakes. The field trip includes a look at earthquake hazards and earthquake risks to the people, infrastructure, and economy of the region. The Earthquake Insight Field Trips were originally sponsored by the US Geological Survey. More recently, the Missouri Seismic Safety Commission and the Missouri State Emergency Management Agency are sponsors. Earthquake Insight Field Trips are led by the author, Phyllis Steckel, RG. Due to Covid-19, Earthquake Insight Field Trips were not held in 2020. However, one is tentatively planned for the fall of 2021. Contact Phyllis Steckel at psteckel@charter.net for more information. CEUs and/or PDHs are available from the University of Missouri – Columbia. Eliza Bryan and her son, Fred Bryan, lived most of the rest of their lives in New Madrid. Fred died in 1865 and Eliza died in 1866. They are buried next to each other in the old New Madrid cemetery, near the corner of St. Isadore and St. Paul drives in New Madrid. Unfortunately, the names and experiences of the hundreds of other New Madrid residents in 1811–12 have been lost to history—or, at least, remain unfound to date. Most who felt these earthquakes were not able to read nor write in any language. But if they could, their recollections may have been in Spanish or French, or even in Native American records, such as winter counts—potential information sources that have yet to be sought out.

The Town of New Madrid, Missouri, in 2021 Today, New Madrid is home to about 3,000 people and the county seat of New Madrid County. Although some of the street names have changed over the years, many of the streets in the oldest part of town are still on the same grid pattern as when they were laid out in the late 1700s. At New Madrid, the Mississippi River flows along the south edge of town, from east to west, across the northern arc of the Kentucky Bend. Being on the outside of this river meander has exposed the townsite to continuous riverbank erosion over more than 200 years. As a result, several streets shown on the earliest maps of New Madrid that were closest to the Mississippi River have been washed away during the many floods that affected the area. Almost all of the land in New Madrid County is now under intense corporate agricultural production, mostly soybeans, cotton, corn, and commercial vegetable crops. The swampy areas around the original townsite have all been drained and cleared by the Little River Drainage District, an ambitious, private, engineered-drainage project installed in southeast Missouri in the early 1900s. Paid for by the landowners within its project area, its installation actually required moving more Summer 2021

material than the Panama Canal and employed some of the same engineers and workers that had just finished up on that project in Central America. Now, there are several large industrial facilities, mostly agriculture-related. One of the United States’ largest and last aluminum smelters is nearby. Now the town of New Madrid is an exit off Interstate 55, and travel that once took days can be completed in less than an hour. The New Madrid earthquake series of 1811–12 is usually not much more than a footnote in most significant conversations, plans, and decisions made in the central United States. The local museum features a small exhibit about the earthquakes, and the telephone exchange building in New Madrid has been retrofit with an exterior steel frame. Local public schools hold earthquake drills annually for students and staff, and the local first-responders (mostly volunteers) receive special earthquake-response training. But overall, the hazard from the New Madrid fault is often given minor and token consideration by elected leaders and industry decision-makers in remote locations. In 2019, earthquake insurance premiums increased by 700–1,000 percent, and the number of residences having earthquake insurance has decreased from more than 60 percent to less than 14 percent in southeast Missouri. The State of Missouri still has no required building code in southeast Missouri; as a result, almost no structures have been built to any seismic-design standard. The land surface on both sides of the Mississippi River has been engineered for intense agriculture; now, any minor perturbation from an earthquake will permanently flood some dry areas and interrupt the precarious engineered drainages. This story of both the geology and the history of the New Madrid earthquakes of 1811–12 is a call to action. Over a million people now live in this epicentral area, including Memphis. Tens of millions now live in the distant areas that were also affected by the earthquakes—St. Louis, Cincinnati, New Orleans, Little Rock, Louisville, and more. When the next significant earthquake, or series of earthquakes, from the New Madrid fault occurs, we can expect to see every problem seen by Eliza Bryan, or President James Madison, or Dr. Jared Brooks who documented what they saw or felt or experienced in 1811–12. Our losses will be larger and our recoveries will take longer. We have much more to lose.

About the Author Phyllis Steckel, RG, Earthquake Insight LLC, Washington, Missouri, has been an active member of the AEG St. Louis Chapter for about 20 years. Currently, she serves as the AEG Region 7 Director, and the lead author of the Geology of the Cities of the World – St. Louis, Missouri USA. Mostly retired now, she has focused her work on geologic hazards in the central US. Previously, she was involved with the AEG San Francisco Section.

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A. Bruce Rogers, PG, Chair The AEG Nashville Chapter has been staying the course this spring, having combined our monthly meetings/webinars on Zoom. We have yet to have in-person meetings, but we can see this happening in August, after summer vacations are over and (hopefully) everyone has been vaccinated. Our student presentation competition in February was well attended and we awarded cash prizes to all our contestants—they were all too good to pick just one winner! We appreciate Professor Andrew Wulff of Western Kentucky University and Professor Arpita Nandi of East Tennessee State University for taking the time to encourage participation from their students. Developing student membership from our regional university geology departments will be the hallmark of my tenure as Chair of the Nashville Chapter. Students stand to benefit more from an AEG membership than any other segment of our profession, and I am making sure that all geology department chairs are aware of the benefits that AEG offers to student members. In March, two of our officers, Katherine Clifton and Caitlan Howard, provided a career day seminar at the geology department of Western Kentucky University that was both well attended and well received. Students were given expert advice on how to network, identify prospective employers, develop interview skills, prepare a resume, and what to expect in today’s field and professional working environment. The seminar was a huge success due to the friendly organization provided by Professor Wulff of WKU and the ability of the students to talk to our younger officers who understand the challenges of beginning a career today. Approximately half of the student geologists we are seeing at all universities are women. I think this is a great endorsement of our profession! In fact, when my term as Chair of AEG Nashville is over in October of this year, all our officers will be women—a fact that I am very proud of. From starting the Chapter in 2017 with only 8 members, we are now at 52 members and still growing. This fall when the new officers take over the reins, it will mark a changing of the guard in that none of the original founders of the Chapter—Mike Arles, Mark Elson, Tom Ballard and myself—will be an officer. From the onset, we set up a structure where the Secretary moves up to Vice Chair and then Chair in successive years to keep experienced officers in the Chapter. This is exactly the way Chapters should evolve, to allow new ideas to develop, to provide opportunity for our membership to become more involved, while at the same time maintaining continuity and focus in our leadership. It has served us well. We continue our efforts to recruit members, pursue grants for our students and provide presentations from throughout the professional geologic community. In March we hosted the 2021 Jahns Lecturer, Cheryl Hapke, PhD, and were grateful for her presentation on landslides along the Big Sur Coast of California. We also hosted American Engineers, Inc., for a webinar on

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geotechnical drilling techniques that was well presented, thanks to Brad High and Dusty Barrett of AEI. In May we had Robert S. Wilkinson of the Tennessee Department of Environment and Conservation provide a presentation on An Update on the State of Coal Ash in TN. This was probably the best environmental presentation we have ever had and on a very relevant topic in consulting geology. I have resumed talks with two K–12 schools in rural Kentucky to provide “Careers in Geology” presentations once the school year begins this August. I think everyone is getting tired of Zoom and ready to get back to some sort of normalcy! After the summer break, we will resume monthly meetings in August and have two field trips tentatively planned in the fall. The first, at Onyx Cave in Kentucky, and the second, at the Gray Fossil site in East Tennessee, to be hosted by our student members at Western Kentucky University and East Tennessee State University, respectively. I will be presenting at the AEG Annual Meeting in September at San Antonio and hope to see all of you there. Mark Elson, Jessica Hinton, and I are also presenting at the Association of State Dam Safety Officials annual conference, also in September, at the Music City Center here in Nashville. Lastly, it has been requested that I run for AEG Director of the Southeast Region. I welcome the challenge, ask for your endorsement and hope that I can be as successful serving AEG in that capacity as I have been here in Nashville. I am a high-energy person, not shy about asking folks to support and join AEG and always try my best to be an advocate for our profession. Have a Great Summer! Editors’ Note: A big Thank You to Bruce for his service as Chair of the Nashville Chapter and good luck in his run for AEG Director of the Southeast Region.

Did You Know? There are a total of 26 Local Chapters and 47 college and university Chapters within the AEG. We would like to remind our Chapter Chairs that your articles in the HOMEFRONT section of AEG News are a great way to promote your Chapter, encourage participation, and boost membership. What activities does your local Chapter have planned as we begin to reconvene for meetings and field trips, recreation and picnics, student nights, etc.? The Homefront is also a place to promote professional and academic research being carried out by local Chapter members, as well as legislative initiatives, lobbying activities, and licensure news. Please keep your community and colleagues updated by sending your articles and photographs to the Homefront (news@aegweb.org). The deadline for the Winter edition is October 26. You can connect to each Chapter’s page by visiting https://www.aegweb.org/regions-chapters. If you are interested in starting a new Chapter, visit https://www.aegweb.org/start-a-chapter.

AEG NEWS 64(3)

Summer 2021

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Summer 2021 Vol. 64 No. 3

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