Speaking of tsunamis, the really worrisome issue is these things happen with alarming regularity, and that the one hitting Asia may be more of a runt of the litter than the supersized version. Back in September of 2001 — it was a busy month for everyone involved in apocalyptic events — warnings were issued about the Cumbre Vieja volcano on the Canary Island of La Palma.
When it lets loose it will cause a mega tsunami so huge it almost defies description — a wall of water hundreds of feet high, reducing to waves a mere sixty to a hundred-fifty feet high after crossing the Altantic; more than sufficient to obliterate North and South America's entire eastern seaboard up to ten miles inland, potentially killing hundreds of millions of people. Yikes! Run for the hills!
Experts describe the resulting tsunami as being impressively large:
The tsunami have been modelled by Steve Ward of the University of California, Santa Cruz and Simon Day of the Benfield Hazard Research Centre (currently at Santa Cruz). In the worst case scenario (for a 500 cubic km collapse), this envisages an initial bulge of water 900 m high. This subsides to form waves in excess of 100 m in height that strike neighbouring islands. After an hour waves 50 - 100 m high hit the NW African coast, while Spain and the UK experience waves 7 - 10 m high two to five hours after collapse. After nine hours, the Florida coastline can expect to face around a dozen waves between 20 and 25 m high.Cumbre Vieja Q&A (PDF)
Three hundred feet is about twenty stories, give or take. But it takes a little creative writing to put that into perspective:
Fortunately the nearest coast to the Canary Islands, where the waves will be around 300 feet (100 metres) high when they hit, is lightly populated Western Sahara. Few people living in the coastal plains of Morocco, south-western Spain and Portugal will survive either, but the waves will drop in height as they travel. The coasts of southern Ireland and south-western England will also take a beating, but by then the wave height will be down to about 30 feet (10 metres).
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 north-eastern Brazil. With a clear run across the Atlantic, the wall of water will still be between 60 and 150 feet (20 and 50 metres) high when it hits the eastern seaboard of North America, and it will keep coming for ten to fifteen minutes.
Worst hit will be harbours 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.Gwenne Dyer
The US government's advice on How to Survive a Tsunami doesn't seem particularly useful in such circumstances. This dire event is, fortunately, not likely to happen next week. (Guess I'll have to put a check in the mail for the car insurance and the phone bill, after all.)
It is unlikely, however, that the collapse is imminent. ... Furthermore, although we cannot say whether the volcano will fail in its next near-summit eruption (like that in 1949; a small eruption in 1971 at the very southern end of the island seems to have had relatively little effect, probably because the magma did not rise so high in the volcano) or only after several more eruptions have progressively weakened it, since eruptions of the Cumbre Vieja occur at intervals of a few decades to as much as a few centuries the year-to-year probability of failure is relatively low. The "half-life-to-failure" of the volcano, if things continue as they are, might be as much as 5000 years - but could be much less.Benfield Hazard Research Centre Report
In the meantime, buying tsunami insurance might not be the best way to spend your money. Neither is waiting for the tsunami to make Manhattan rents — or Brooklyn for that matter — affordable again.