The nearest coast to the Canary Islands, where the waves will be around 100 meters high when they hit, is the sparsely-populated Western Sahara. Few people living in the coastal plains of Morocco, Portugal or Southwestern Spain will survive either, but the waves will drop in height as they travel. The coasts of Southern Ireland and Southwest England will also take a beating, but by then the wave height will be down to about 10 meters.
The real carnage will be on the western side of the Atlantic, from Newfoundland all the way down the east coast of Canada and the United States to Cuba, Hispaniola, the Lesser Antilles and Northeast Brazil. With a clear run across the Atlantic, the wall of water will still be between 20 and 50 meters high when it hits the eastern seaboard of North America, and it will keep coming for ten to fifteen minutes.
Worst hit will be harbors and estuaries that funnel the waves inland: goodbye Halifax, Boston, New York, Philadelphia, Baltimore and Washington, DC. Miami and Havana go under almost entirely, as do low-lying islands like the Bahamas and Barbados. Likely death toll, if there is no mass evacuation beforehand? A hundred million people, give or take fifty million.
The western flank of Cumbre Vieja volcano on the island of La Palma in the Canaries is going to slide into the Atlantic one of these days: a diagonal fracture has already separated it from the main body of the volcano, and only friction still keeps it attached. ﾓWhen it goes, it will probably collapse in about 90 secondsﾒ, said Professor Bill McGuire, director of the Benfield Grieg Hazard Research Center at University College London. And when it goes, probably during an eruption, the splash will create a mega-tsunami that races across the Atlantic and drowns the facing coastlines.
The last time the volcano erupted, in 1949, its whole western side slid four meters down towards the sea, and even now it is still slipping very slowly downwards. Given the scale of the catastrophe if the next eruption sends this mountain crashing into the water, Dr. McGuire is angry that there is so little monitoring equipment on La Palma to give advance warning: ﾓThe US government must be aware of the La Palma threat. They should certainly be worried, and so should the island states in the Caribbean that will really bear the brunt of a collapse.
ﾓTheyﾴre not taking it seriously. Governments change every four or five years and generally theyﾴre not interested in these thingsﾒ. It was a classic scene, revisited in every natural disaster movie: crusading scientist calls feckless governments to account, squalid politicos ignore the call. The science journalists couldnﾴt wait to get their pieces into print.
But hold on a minute. Havenﾴt we heard about this threat before? Whatﾴs new this time? Nothing, except that there hasnﾴt been a stampede to cover La Palma with seismometers. Now, why do you think that is?
Suppose that the governments whose coastlines are at risk, from Morocco to the United States, did get a warning that Cumbre Vieja was waking up again. What would they do with the warning? Evacuate one or two hundred million people from the low-lying lands indefinitely?
They donﾴt know if there is really going to be an eruption (seismology is not that precise), or how big it will be, or whether this will be the one that finally shakes the side of the mountain loose. It could happen in the next eruption, but it might not happen for a thousand years.
No national leader wants to evacuate the entire coast for an indefinite period of time, causing an economic and refugee crisis on the scale of a world war, for what might be a false alarm. But nobody wants to ignore a warning, and perhaps be responsible for tens of millions of deaths. From a political standpoint, itﾴs better not to have the warning at all.
Natural disasters that can affect the whole planet are known to scientists as ﾓglobal geophysical eventsﾒ — gee-gees, for short — and they come in two kinds: ones you might be able to do something useful about, and ones you canﾴt. When governments are faced with the first kind, they can respond quite sensibly.
Since we first realized two decades ago that asteroids and comets smashing into the earth have caused a number of mass extinctions, a US government project has identified and started to track 3,000 ﾑnear-earth objectsﾴ whose orbits make them potentially dangerous. In another generation, we may even be able to divert ones that are on a collision course — and if thereﾴs one gee-gee that you would want to prevent above all others, thatﾴs the one. But thereﾴs no similar remedy on the horizon for volcanoes or earthquakes, or the tsunamis they might cause. On this one, we just have to keep our fingers crossed.
By Gwynne Dyer, Monday Morning, mmorning.com
