An Innovative Technology to Save Lives

Using lessons learned from tragedy and collaboration to protect coastal populations from tsunamis

On March 11, 2011 a 9.1 magnitude earthquake erupted 81 miles off the eastern coast of Tohoku, Japan. The Tohoku Earthquake (often referred to as Fukushima) was the fourth largest earthquake ever recorded. In addition to the impacts felt as far south as Tokyo, the earthquake sent tsunami waves speeding into the Japan coast and out across the Pacific Ocean. NOAA’s Pacific Tsunami Warning Center reported a wave with maximum height of 9.15 feet at an observing station at Hanasaki, Hokkaido, 5.7 feet at Kahului, Maui, Hawaii and 6.6 feet at Crescent City, California.

This tragic event resulted in many lives lost in Japan, and if not for NOAA’s work in developing a more effective tsunami warning system, then many lives could have been lost in Hawaii as a result of the tsunami’s impacts. The Deepocean Assessment and Reporting of Tsunamis (DART ) buoys near Japan were used to produce the world’s first forecast of tsunami flooding for Kahului (figure 2) and other locations in Hawaii. Evacuations were issued six hours before the tsunami struck. Lives were saved.

Figure 2. A graphic of the DART system.

The coastal communities in Alaska, Hawaii, and on the U.S. west coast are in seismically active regions that can generate tsunamis, therefore NOAA initiated research in the 1980s to develop direct measurement of tsunamis in the open ocean. The DART deep ocean tsunami detection buoys were established as a real-time reporting network of these measurements, and sent real-time reports to warning centers to improve the assessment of the tsunami hazard.

The DART was conceived as part of the U.S. National Tsunami Hazard Mitigation Program (NTHMP), which was created as a result of congressional direction to NOAA in 1995. The program’s mission was to lead a federal/state working group to develop a plan for reducing tsunami risk to U.S. coastal communities. Within a couple decades, DART was created, tested and validated, and became part of NOAA’s tsunami warning operations.

This successful DART tsunami forecast capability was not only useful to U.S. interests. Today, in addition to 39 US operated DART buoys, there are 37 operated by global partners across the Pacific and Indian Oceans.

Since the beginning of the 20th century – more than 500 people and $1.9 billion in property have been lost in U.S. states and territories due to tsunami impacts. Studies suggest a large tsunami could affect millions of Americans and cause tens of billions of dollars in damage. Tsunamis cannot be prevented, but their impacts on life, property, and the economy can be greatly reduced.

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The National Tsunami Hazard Mitigation Program includes not only NOAA, but the Federal Emergency Management Agency, the U.S. Geological Survey, and 28 U.S. states and territories. Their vision is to reduce loss of life and property when a tsunami strikes, and they accomplish this through collaboration, coordination, and financial and technical support to partner states. NTHMP and its partners are committed to mitigating the impact of tsunamis through public education, community response planning, hazard assessment, and warning coordination. Their work in education and outreach increase awareness and encourage preparedness through programs like the National Weather Service’s TsunamiReady program, which improves public safety before, during and after tsunami events.

The NTMP works closely with another critical resource, NOAA’s Center for Tsunami Research at the Pacific Marine Environmental Laboratory, which develops models and inundation maps for faster and more reliable forecasts of tsunamis. Through warning coordination, the NTHMP provides input to the U.S. Tsunami Warning System so that warning system products are effective during a tsunami warning.

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The NWS’s Tsunami Warning Centers – the National Center, which serves Alaska, Canada, and the continental United States; and the Pacific Center, which serves Hawai’i and U.S. territories in the Pacific and Caribbean – analyze seismic and sea-level data from around the world, and provide information about an earthquake’s location, depth and magnitude utilizing the DART system for alerting if an earthquake has the potential to cause a tsunami.

We have learned many lessons from past Tsunamis. As a result, the nation’s ability to respond to a tsunami has come a long way since 1995. Much of this progress is because of the NTHMP and its partners, both individually and collectively. Today, thanks in part to the work of the NTHMP, PMEL, TsunamiReady, and the Tsunami Warning Centers, U.S. coastal communities are better prepared to protect people and property from the impacts of future tsunamis. For more information, visit https:// nws.weather.gov/nthmp/.

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