Canary Islands landslides and mega-tsunamis: should we really be frightened?

What is the reality behind stories of mega-tsunamis wiping out the American east coast and southern England? Very little, according to Dr Russell Wynn and Dr Doug Masson from Southampton Oceanography Centre, who have been studying Canary Islands landslides for many years. Their research has shown that stories of a devastating 'mega-tsunami' some 300 feet high and travelling at 500 mph are greatly exaggerated, and that reports suggesting tens of millions of people could be killed have little basis in reality.

Dr Russell Wynn said, "The Canary Islands are volcanic islands that collapse at regular intervals in geological time. However, it is important to remember that in the last 200,000 years there have only been two major landslides on the flanks of the Canary Islands. At SOC we have studied previous Canary Islands landslides to understand how they move, and have found good evidence to show that the landslides actually break up and fall into the sea in several stages.

"By analogy, if you drop a brick into a bath you get a big splash, but if you break that brick up into several pieces and drop them in one by one, you get several small splashes. Therefore a multi-stage failure would certainly not generate tsunamis capable of damaging the coastlines of southern England or the American east coast, although they may have an impact on nearby Canary Islands."

Dr Wynn added, "The mega-tsunami scenario currently being aired in the media is a hypothetical 'worst case', and is largely based upon speculative computer models of landslide motion and tsunami generation. In contrast, our work involves study of actual landslide deposits."

In October 2004 Dr Wynn and Dr Masson will lead a new UK research cruise to the deep ocean offshore of the Canary Islands. The aim is to look in more detail at the deposits of previous Canary Islands landslides in an attempt to better understand how they move, and whether they are capable of generating tsunamis. Dr Wynn concludes, "Only by assembling all the facts and working together can we as scientists provide the public with the best information on these spectacular, but rather infrequent, natural hazards."

Dr Russell Wynn and Dr Doug Masson's research has been funded by the Natural Environment Research Council and the European Union.