Sue Dawson Will climate change in the Arctic increase the landslide-tsunami risk to the UK?

Climate change and landslide-tsunami risk Will climate change in the Arctic increase the landslide-tsunami risk to the UK?

WB 2:

Onshore tsunami deposits

Sue Dawson Fraser Milne, Alastair Dawson, Pedro Costa, David Long, David Tappin Cechr Conference 5th Feb 2014

The Arctic is undergoing rapid change which has the potential to impact the UK and the rest of the world. Understanding what drives this unprecedented change and its possible future consequences is a scientific challenge of the utmost urgency with important societal implications.

Changes in the Arctic affect the nature and frequency of extreme weather events and other natural hazards which threaten the UK.

Key Q-

Key Question:

• Is there evidence of regional tsunami deposits coeval with other very large Holocene Norwegian Sea and Arctic slides? As this may be only evidence that they are tsunamigenic. • If there is an absence of evidence then the failure mechanism of landslides becomes important in assessing the risks to the UK. Cechr Conference 5th Feb 2014

Model Storegga Landslide c 7ka Jon Hill (Imperial College) 2014

Latest numerical model Jon Hill (Imperial College) 2014

Cechr Conference 5th Feb 2014

Why? How ? ď‚— Storegga tsunami deposits widely recognized

Shetland Isles palaeo-tsunami deposits 3 Holocene examples 1. Tsunami ca. 500 AD

2. Storegga tsunami ca. 7,2000 BP

Tsunami into lakes 3. Loch of Benston, Shetland cores c.4500 BP

Run up potential

• A revised chronology of potential tsunami deposits in Shetland, mainland Scotland, the Hebrides, NE Iceland and E Canada • Broadening the range of field study to constrain the age and distribution of all events, particularly younger Holocene tsunami, currently restricted to Shetland

Work Block 2

Work Plan  Field survey to identify new sites in Shetland to determine the extent of events younger than Storegga.

 Field constraints on sea level histories - tsunami run-up height to be used to calibrate numerical models and to assess magnitude and damage potential.

 Broader geographic range of field studies.    

Northern mainland Scotland (Loch Erribol, Kyle of Tongue) Outer Hebrides (Rosnish, Benbecula) Iceland Coast of Newfoundland/Nova Scotia (Canada)

Cechr Conference 5th Feb 2014

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Database

Cechr Conference 5th Feb 2014

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Fieldwork – Iceland - Breiddalsvik

Cechr Conference 5th Feb 2014

Fieldwork – Iceland - Austerhorn

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Cechr Conference 5th Feb 2014

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Fieldwork - Iceland

ď‚— Only when a selection of key factors (i.e. coastal geomorphology; accommodation space; sediment availability; sediment source; wave regime) occurs, tsunami events can be recorded and preserved in the stratigraphy

Cechr Conference 5th Feb 2014

Fieldwork – Shetland – June 2013

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Cechr Conference 5th Feb 2014

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Fieldwork – Shetland – Mid Yell Voe

Cechr Conference 5th Feb 2014

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Fieldwork – Shetland – Whale Firth

Cechr Conference 5th Feb 2014

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Fieldwork – Shetland – Basta Voe

Cechr Conference 5th Feb 2014

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Fieldwork – Shetland  Mid-Yell Voe’s stratigraphy presented 3 sand layers.  Whale Firth’s sand layer was the highest detected  Garth’s Voe has a complex stratigraphy  Basta Voe sand layer was traced further inland than previously known.

Cechr Conference 5th Feb 2014

Improved Holocene RSL curve to constrain runup of tsunami events for peripheral areas of Scotland as well as NE Iceland and Labrador •Run up height needed to calibrate the models (WB 5) & assess magnitude (WB 6) •Sea level curve, poorly constrained for N Scotland Liase with GIA modellers Peltier & Drummond, Canada

Thank you