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Unscheduled Earthquakes

Earthquakes don't happen on schedule. That's the one intrinsic flaw with the Great Southern California Shakeout, an earthquake simulation exercise in Los Angeles scheduled for Nov. 13 at 10 a.m. Sure, it's a good idea. People need to be prepared. But the very nature of earthquakes is that they're unpredictable. They're not entirely "random," of course -- we understand how they're driven by tectonic forces, thanks to the very successful theory of plate tectonics developed in the 1960s -- but they seem to be pretty darn chaotic.

I have a story in the paper today on this subject. It includes what I hope is a reasonably calm and rational discussion of the potential for a catastrophic earthquake in Los Angeles. (In real life the biggest earthquakes in an area like LA are magnitude 8, but in the movies, LA earthquakes are magnitude 11, and usually come in tandem with volcanoes, tidal waves, plagues of locusts, epidemics of eschatological thinking, etc.

Everyone knows that LA will eventually have a big earthquake, though whether it happens tomorrow or in 50 years is impossible to say. It could be a big rupture of the San Andreas Fault, or a quake caused by one of the many other thrust faults (some of them called "blind thrust faults" because they don't reach the surface) that lie under the LA basin and among the surrounding mountains. Northern California could have one, too, perhaps on the Hayward Fault that runs through Berkeley and Oakland and down toward San Jose. Or there could be one on an off-shore fault. Or -- leaving California behind -- on the subduction zone off the coast of the state of Washington. Or on the New Madrid Fault that's right in the Mississippi valley. Even Manhattan could get a big earthquake, or New England.

When I did my research for the earthquake article in National Geographic a few years ago, I traveled the length of the San Andreas Fault, from way up in Northern California, in misty redwood country, all the way down to Bombay Beach, a hellish and largely unoccupied village that bakes on the shore of the Salton Sea. In between I saw where the San Andreas slices through suburban neighborhoods near San Francisco; where it crinkles the earth in the Carrizo Plain; where it brings just enough water to surface to allow the oasis that is Thousand Palms. What's certain is that southern part of the fault hasn't broken since the late 1600s. Is it due? Maybe so. But even that is a guess.

All of which is a reminder to give doubt a chance.

Here are some key graphs in my story:

For years, scientists have debated whether earthquakes are in any way predictable. There's a divide between those who see them as innately chaotic and those who think there are discernible patterns, even precursors, that would make it possible in theory to know when the Big One is coming.

Scientists don't try to predict earthquakes, but they do produce scenarios and hazard maps. The problem is that the planet doesn't seem to pay close attention to the maps or abide by statistical probabilities. The Great Sumatra-Andaman earthquake on Dec. 26, 2004, which caused a catastrophic tsunami, happened on a known fault, but the fault broke much farther to the north than anyone had anticipated.

The Northridge quake of 1994 took place on an unknown "blind thrust" fault beneath the surface of Southern California. More blind thrust faults have been found since, including the Puente Hills thrust fault running beneath downtown Los Angeles. There's no reason to think the census of such subterranean features is complete.

"We don't really understand the Earth," said Thomas Jordan, director of the Southern California Earthquake Center. "There may be faults we don't even know about."

Here's a web page with estimates of the probability of earthquakes in California. Note the maps on the right.


More science: Via Drudge we see this NASA press release on a new probe going to the sun. One of these days I want to do a big story on Our Friend the Sun, which is, sadly, sometimes not very friendly at all (what with those nasty Coronal Mass Ejections and whatnot). The press release includes a couple of interesting solar mysteries:

Mystery #1--the corona: If you stuck a thermometer in the surface of the sun, it would read about 6000o C. Intuition says the temperature should drop as you back away; instead, it rises. The sun's outer atmosphere, the corona, registers more than a million degrees Celsius, hundreds of times hotter than the star below. This high temperature remains a mystery more than 60 years after it was first measured.

Mystery #2--the solar wind: The sun spews a hot, million mph wind of charged particles throughout the solar system. Planets, comets, asteroids--they all feel it. Curiously, there is no organized wind close to the sun's surface, yet out among the planets there blows a veritable gale. Somewhere in between, some unknown agent gives the solar wind its great velocity. The question is, what?


What great dishing from Lebo in that NY paper about the Clintons' Enemies List (which includes an entire state!):

'Several names and entities are common among various list makers. The lineup invariably begins with A-list members like Gov. Bill Richardson of New Mexico; Representative James E. Clyburn of South Carolina, the House Democratic whip; Gregory B. Craig, Mr. Clinton's lawyer in his impeachment and trial; David Axelrod, Mr. Obama's chief strategist; Senator Claire McCaskill of Missouri; and several Kennedys. Some members of the Democratic Party's rules committee, the state of Iowa and the caucus system in general are also near the top.

'The news media have already focused on some list entries, including the online gossip purveyor Matt Drudge (who had the nerve to show up at Mrs. Clinton's departure speech on Saturday), Todd S. Purdum of Vanity Fair (the author of a recent profile of Mr. Clinton) and the cable network MSNBC (whose hosts Chris Matthews and Keith Olbermann are charter list members, Clinton associates said).'

By Joel Achenbach  |  June 11, 2008; 10:39 AM ET
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