Tsunamis: Who’s at Risk?

March 15th, 2005 by

We don’t often refer readers to a single site, but today we make an exception for an extraordinary explication of Tsunamis to be found at Guy Carpenter, a risk and insurance subsidiary of March & McLennan Companies. In this elegant and comprehensive document, we learn the science of tsunamis — where and how they originate and the magnitude of their destructive powers. We learn not only about what happened recently, but of the risks for similar incidents that exist all across the globe.
Last year’s disaster was triggered by the 4th largest earthquake since 1900. There have been incidents of even greater scale, but the impact was mitigated by smaller water-side populations. These days it seems that everyone wants to be near the water. A volcanic eruption on the Greek Island of Santorini in 1638 B.C.triggered a tsunami 165 feet high, which was felt across the Mediterranean (the more recent incident in the Indian Ocean topped out at a mere 50 feet). During the First World War, a French munitions ship, the SS Mont Blanc, collided with another vessel and exploded, sending a 60 foot high wall of water into Halifax, Nova Scotia, killing over 2,000 people.
Avoiding Tsunamis
If you are trying to gauge your personal risk in this terrifying area, the risk analysts at Guy Carpenter suggest that the Indian Ocean is most likely to suffer a tsunami, with the Pacific Ocean (and our own west coast) at higher risk than the Atlantic coast. But east-coast dwellers have no reason to sleep smugly in their ocean-view beds. If the Cumbra Vieja volcano on the island of Palma were to erupt (and it will within a hundred years or so), it is likely to trigger a huge landslide that may in turn produce a tsunami that would bring 33 to 82 foot waves against the Atlantic coastline. Those dwelling on the coast can do their own math.
We offer these thoughts not to depress, but to enlighten. Let’s remember that for all our actuarial expertise, for all our sophisticated risk evaluation, we live on a volatile planet.
(Kudos to the authors, Julian Alovisi, Nick Hassam, David Logan and Angus Milligan. And thanks to our colleague Peter Rousmaniere for pointing the way to this fascinating document.)