I Feel the Earth Move Under My Feet

Thursday, May 17, 2007

I live in Earthquake Country and we had a fine little one yesterday: a nice, sharp boom-shudder that sounded and felt like a fully loaded cement truck had run into our living room. Somewhere in the house, something I still haven't found fell off of something else and hit the floor. My wife and I looked at each other, our attention quite engaged, and flinched through that fraction of a second of waiting to see if it stopped or got worse. It stopped.

Our sport is guessing whether a temblor is small and nearby or large and distant. This was certainly the loudest one I can remember but it left nothing swaying, so I guessed it was a pip-squeak magnitude 2 directly underfoot. My wife was more impressed and guessed a magnitude 4 farther away. The U.S. Geological Survey has a nice website that within 10 minutes told us it was a magnitude 3 whose epicenter was four miles beneath a high school less than a mile from our house. We called that one a tie.

Magnitude 3 is nothing, a trifle. My personal best was of course the magnitude 7 Loma Prieta quake of 1989, which knocked a section out of the Oakland Bay Bridge and interrupted the Giants vs. A's World Series. I was working as a supervisor in an environmental chemistry lab at 5:04 p.m. on October 17 when the earth broke 110 miles away. I suddenly felt dizzy and thought it was just me until I saw everyone else reeling, too. Now, the official advice is to stay indoors and ride it out under a sturdy piece of furniture; in 1906, a lot of people were killed when they ran outdoors and got clocked by falling debris. All I know is that everyone in the lab simultaneously realized they did not want to be inside a concrete slab building filled with hazardous and flammable chemicals and gases if it decided to come down. I got behind my co-worker Ken, who is about 6-foot-7 and 250 pounds, and followed him out like a running back on the heels of a blocker. Out in the parking lot I saw the most amazing sight: asphalt rippling like waves on the ocean, with parked cars bobbing up and down like boats. It was, frankly, both deeply disturbing and really cool.

(I imagine my friend Sherwood, whose home I reckon was right on top of the Loma Prieta epicenter, has a much scarier story to tell, assuming he was in the area at the time.)

There's a kind of irrational, fatalistic insouciance that goes with living in Earthquake Country. I think you either get used to the idea that the world can shake itself to bits at any second or you move away. I have a friend who grew up near my neighborhood back when it was a plum orchard and remembers how the neat ranks of trees were split and offset by the faultline that ran through them. I always laugh when I tell people that, although it's not really funny. But the fact is that, although some locations are better than others--bedrock beats alluvial plain--almost nowhere on the West Coast is safe.

I don't believe in fate but I do trust probabilities and statistics. Big quakes happen on scales of decades to centuries, while major quakes (like 1906) happen on scales of centuries to millenia. Modern building codes give me some confidence that my wood-frame home will survive anything short of total disaster. We take the prescribed precautions. All in all, I'll be here a relatively short time (geologically speaking) and like my odds better than if I resided in Tornado or Hurricane Alley. For us, living here is worth the risk. Still, it's interesting to get a little kick in the pants once in a while. Makes you think.


My Little Earthquake, all over in
about half a second (courtesy USGS)
.

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