The Finch Formerly Known As Gold

27 December 2004

Can it happen here?

A quake of magnitude 9.0 is almost unimaginable. The worst in the past century was a 9.5 quake (six times as severe) that struck the coast of Chile in 1960; nearly a thousand miles of fault line ruptured, and 80-foot waves were reported. Just over two thousand people were killed.

Still, in terms of sheer destructiveness, the 9.0 temblor off the coast of Sumatra is more than holding its own: deaths are now over ten thousand, and 40-foot waves have been reported more than half a mile inland in Sri Lanka.

Andrea Harris doesn't wonder what a disaster like that would do to Florida:

[T]here is little to no high ground in my entire state until you get near the Georgia border; if a tidal wave as big as this one hits we're pretty screwed. We're also close to the Caribbean, where they have live volcanoes.

You have to figure that any tidal wave big enough to reach Oklahoma has already taken out Louisiana and much of Texas, but we have more than our share of earthquakes. The Meers fault in the southwestern part of the state is big enough to see for much of its 16-mile length; it was relatively dormant for a few millennia, but then exploded about 1600 years ago into a quake estimated at magnitude 7.0. The worst quake to hit the state in recent years, though, wasn't along the Meers, but along a fault line running from El Reno to Kingfisher; it struck El Reno in 1952.

A bigger danger, perhaps, comes from the New Madrid fault line, which runs from southern Illinois down the Missouri bootheel into northeastern Arkansas, crossing the Mississippi River three times (and the Ohio twice) along the way. In the winter of 1811-1812, three successive 8.0-plus quakes laid waste to the Mississippi Valley; church bells rang as far away as Boston. There is, say some experts, about a 1 in 4 chance of a quake as large as 7.5 between now and 2040, which would be enough to cause damage in northeastern Oklahoma; the chance of at least a 6.0 by 2040 is almost 90 percent.

The worst earthquake recorded in North America US struck Prince William Sound in Alaska in 1964; it was somewhere in the high eights, maybe low nines, about a point above the San Francisco quake of 1906.

I still plan to sleep tonight.

Posted at 6:31 AM to Soonerland

TrackBacks if any:

You may want to check out the following map:

http://eqhazmaps.usgs.gov/images/homepage.gif

and its source page:

http://eqhazmaps.usgs.gov/html/map_graphic.html

on the probabilities of severe earthquakes in the United States in the next 50 years.

Posted by: Michael Meckler at 8:29 AM on 27 December 2004

When I lived in Japan, we had PLENTY of warning when tsunnamis were expected. I couldn't understand the announcers, but I could read the flashing red coastlines on the map.

Not that they applied to me - I lived about 15 miles inland.

Anyway, these countries didn't have a warning system in place. What a tragedy. With few exceptions, you get quite a bit if warning before tsunamis hit.

Posted by: Dan at 11:22 AM on 27 December 2004