Saturday, June 24, 2006

The Next Big One Could Come Any Minute Now

Some people say that California really isn’t so bad, despite its faults. Ok, sorry about the bad pun, but those kinds of faults exist in the Midwest, too, including Indiana. Another thing they say about faults is that they are like people; they keep building up stress until, eventually, they snap.

That snap can be felt as an earthquake. And, like with people under stress, the longer a fault goes without snapping, the bigger the resulting earthquake will be.

Geologists have recently concluded that the part of the San Andreas Fault that runs through Southern California, including Palm Springs and Los Angeles, has built up about 300 years of stress. That means it could let go any minute now. The average time between major quakes in that region is 250 years.

Actually, the exact prediction is that there is a 70 percent chance of a major earthquake sometime during the next 30 years. Predicting earthquakes is far less accurate than predicting the weather, which is still not too exact going beyond tomorrow.

It still makes me glad I don’t live in California, though. In Indiana, we have tornadoes. But one can go an entire lifetime without ever seeing a twister. In fact, most people in Indiana live out their lives without seeing one up close and personal.

But in California, no one escapes earthquakes. They have relatively minor quakes all the time, and most people get used to them. But a major earthquake along the San Andreas Fault will happen. That’s a certainty.

In a sense it’s like being able to predict that a tornado will definitely hit downtown Franklin. We just don’t know exactly when but there’s a 70 percent chance it will be within 30 years.

The odds that a tornado will actually hit downtown Franklin are nowhere near that great. Yet, it could happen, and that fact is what Midwesterners learn to live with.

But, since I’m talking odds, it might surprise you to know that the odds that a major earthquake will strike Southern Indiana are greater than the odds of a twister striking any single place over the same time period.

Seismologists, the people who study and try to predict earthquakes, say that when the San Andreas Fault does finally slip, the resulting earthquake will be at least an eight on the Richter scale. It would be devastating.

But the largest quake ever to hit the United States occurred in December, 1811. Its aftershocks continued into the following year. And, no, it was not in California. The epicenter was near the town of New Madrid, Mo. And it was felt throughout much of the Midwest, including Indiana.

Fault lines in the New Madrid system of faults run along the Mississippi and Ohio River basins. Earthquakes large enough to be felt are rare in these parts, but they do happen.

There was a noticeable trembler that occurred in 1968. It was during the presidential campaign and one of the local newspapers quipped, “Nixon said he had some earth-shaking ideas, but this is ridiculous.”

In the mid-1980s, I was sitting on the deck of my home in Hobart, where I lived at the time. I thought I felt something, as if I were in a boat. I looked at the kids’ swing set and noticed the swing had begun to oscillate. I checked the news and it was, indeed, an earthquake.

But those were small earthquakes. We’re all waiting for “the big one” to strike California. And, indeed, it may strike at any time. But an equally big one could strike anywhere between Memphis and Evansville. And as difficult as it is to predict earthquakes in California, earthquakes in the Midwest are even more mercurial.

After all, the last big one to strike the Midwest changed the course of the Mississippi River and sent coal hurling skyward from fissures that opened in the earth. And that was long before Hollywood invented such scenarios.

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