When I was in high school, my favorite history teacher would occasionally joke that his efforts to educate the students of South Florida would be for naught, as at some point a tsunami would wipe out the east coast of North America. He also insisted that a similar event would demolish the west coast, leading him to toy with the idea of retiring somewhere in the Alps. The idea of tectonic activity causing a cataclysmic wave sometime in the geologic future had enough prima facie plausibility that I didn’t think about it any further.
Now I have, and as it turns out, it’s bollocks.
For the uninitiated, tsunamis are massive standing waves caused by tectonic activity and similar events on or near the ocean floor. As was amply and tragically demonstrated in 2004, their destructive potential is massive. The coast of Sumatra was so shifted by this explosive energy release that its outline is now visibly different from space. The Pacific and to a lesser extent the Indian Oceans experience numerous tsunamis of varying strength each year, with only a few approaching the size of the 2004 event. Tsunamis also occur in the Atlantic, most famously in the aftermath of the 1755 Lisbon earthquake that is sometimes used to calibrate the Richter scale. Some tsunamis are induced or augmented by underwater landslides that follow the initial earthquake, becoming much more powerful “megatsunamis.”
In 1999 and 2001, two geologists proposed that tectonic activity in one or more of the places on the short list of active sites in the Atlantic—the Azores and the Canary Islands—might induce a megatsunami of concern to the regions bordering the Atlantic.
Naturally, a few games of “science telephone” turned this conclusion into the imminent collapse of Western civilization thanks to a rogue wave from the outlying Spanish or Portuguese islands. From there, the rush of credulous land purchases in Colorado. One can imagine the smug looks on people’s faces, as they snapped up what they probably expected to become prime oceanfront property within a few years in advance of a new incursion from Iberia that probably scares them less than the one that passed through Mexico first.
What one has to wonder is whether the people fleeing the coastlines in pre-emptive terror ever notice that the English word for tectonic waves is of Japanese origin…because this kind of activity is almost unheard of in the Atlantic. Indeed, studies have shown that tectonic activity in the Atlantic can’t produce the kind of continent-scouring wave that made the news in 2004. The Atlantic Ocean’s largely passive continental margins and lack of subduction zones mean it rarely produces tsunamis, and its huge midocean ridge means that tsunamis have difficulty propagating from one side of the ocean to another, a problem they do not face in the Indian and especially the Pacific Oceans. The last tsunami to cross from the eastern to the western Atlantic coasts made the outermost Caribbean island, Barbados…notice some unusual waves.
So, when the La Palma volcano finally erupts and gives these people the event they’ve been waiting for…it won’t be so much a coastline-erasing monster of water and death as a nasty mess for the people of Spain and some enhanced surfing in St. Lucia.
I suppose I should be flattered that some credulous people think so highly of my great-grandfather’s people that damage to one of their islands is enough for them to declare the end of the world. Flattered, but not impressed.