Wednesday, August 24, 2011

All Shook Up

Earthquakes are different in the eastern United States than in the western United States, a fellow with a geological background was saying yesterday following the earthquake in northern Virginia.

I didn't catch everything he said because I was channel surfing, and I came across him midway through his segment, but I gathered from what I heard that the fault lines along the west coast are more active than the ones on the east coast.

I guess I didn't need anyone to tell me that. Folks speak of the period between earthquakes in California in terms of years — decades at the most.

Earthquakes in the eastern United States happen about once every 500 years. The fault line that was responsible for the 5.8 earthquake that shook the east coast yesterday may not even have a name.

The eastern earthquakes also don't pack the kind of punch that the earthquakes in places like California and Japan do. Something about how the fault lines along the east coast fill with accumulated sand and sea debris, making the seismic activity less intense — but, at the same time, helping to make it possible for the quake to be felt from greater distances.

That is why, this fellow was saying, an earthquake in northern Virginia is not as destructive as the 7s and 8s we've seen along the Pacific, but it could be felt in the Carolinas or Georgia as well as the much closer city of New York. I've also heard that it could be felt as far west as Chicago.

Now, science was never my strong subject in school so I have a little trouble understanding that part of it.

Wish I had caught the first part of what he was saying. Wish I knew more about why some earthquakes are more destructive than others — even when they strike areas that expect them and go to great lengths to be prepared for them.

A friend of mine moved to New York a few years ago. Yesterday, he posted on Facebook that he was sitting on his bed when the earthquake struck, and his bed shook.

I had some friends who lived through the San Francisco earthquake in 1989. They told me that their friends out there, who had joked for years about "the Big One," called that earthquake the "Pretty Big One." It only measured 6.9, and it only lasted 15 seconds, but it resulted in 63 deaths and more than 3,700 injuries.

There was also quite a bit of property damage.

Apparently, there was some damage yesterday as well, but it will take awhile to determine the extent. Most of it appears to have been done to older buildings that are ill prepared for an earthquake of just about any magnitude.

And I have heard no reports of deaths or injuries.

In fact, what happened along the east coast yesterday seems to be similar to the kind of thing that has been happening in recent years in my home county in central Arkansas. It is not far from the New Madrid Fault in the central United States that allegedly caused an earthquake in the 19th century strong enough to ring the bells in Boston.

Anyway, there was a series of earthquakes in my home county in the spring — most of which measured in the 3s, which admittedly isn't strong enough for most people to notice.

A 5.8 earthquake is strong enough to notice but not usually strong enough to cause death or injury — unless it strikes severely underdeveloped places. The government in D.C. may be dysfunctional, but the city itself is not underdeveloped.

Thus, I figured it wouldn't be long before some people began poking fun at the exaggerated response to the earthquake.

No deaths. No injuries. The most serious damage, by far, appears to have been psychological.

In both Washington and New York — and other places along the Eastern Seaboard — nerves are on edge less than three weeks before the 10th anniversary of September 11. And, as Marc Fisher reports in the Washington Post, terrorism was the first thought to cross the minds of lots of folks in D.C. yesterday afternoon.

And why not? An airplane piloted by a Islamic extremist crashed into the Pentagon a decade ago. The last earthquake on the east coast may predate the American Revolution.

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