Understanding tsunami threats to UK coasts
The UK has been hit by significant tsunamis in geologically recent times, but what is the likelihood of a future tsunami reaching our shores this century, and what would the economic cost of such a disaster be?
It has been proposed that future collapse of the west flank of La Palma, the westernmost of the volcanic Canary Islands off northwest Africa, could generate a catastrophic ‘mega-tsunami’ capable of wreaking havoc on both sides of the Atlantic Ocean. This story generated huge media interest and caused significant ripples in the reinsurance sector.
However, detailed studies undertaken by NOC scientists on submarine landslide deposits around the Canary Islands have discovered that these events are extremely rare, averaging only one every 100,000 years1. Sampling of offshore landslide deposits has also found evidence that these vast failures occur in multiple stages1,2. If a future landslide also occurred in multiple stages, the tsunami threat away from the immediate source area would be greatly reduced. These results contributed to a report to UK government, which can be downloaded at:
http://www.defra.gov.uk/environment/flooding/risk/tsunami.htm
NOC scientists are currently investigating whether global warming impacts on the deep ocean could trigger a future tsunamigenic landslide in Arctic and sub-Arctic regions, with potential impacts for UK North Sea coasts3. A collaborative partnership with tsunami modelers and the reinsurance industry has now been established to assess the potential hazards and economic implications of such an event.
References
1 Masson, D.G., Harbitz, C.B., Wynn, R.B., Pedersen, G. and Løvholt, F. (2006) Submarine landslides: process, triggers and hazard prediction. Phil. Trans. Roy. Soc. A, 364, 2009-2039.
2 Wynn, R.B. and Masson, D.G. (2003) Canary Islands landslides and tsunami generation. In: Proc. 1st Int. Symposium on Submarine Mass Movements and their Consequences (Ed. by J. Mienert and J. Locat), Kluwer, Dordrecht, 325-332.
3 Berndt, C., Brune, S., Nisbet, E., Zschau, J. and Sobolev, S.V. (2009) Tsunami modeling of a submarine landslide in the Fram Strait. Geochemistry, Geophysics, Geosystems, 10, Q04009.
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