Tuesday, August 23, 2011

Earthquake in Virginia

A few minutes ago, at 1:51 p.m, a magnitude 5.9 earthquake rattled Northern Virginia between Richmond and Washington. That's no small potatoes. Five nine is enough to crack foundations, knock things off shelves, and cause spontaneous pants wetting among people who have never been in or close to an earthquake. On the West Coast, 5.9 would be something to talk about for a week, but not a big deal. For context, the Japanese earthquake this spring and the 1964 Alaska earthquakes were over one thousand times stronger than this one.

Not all earthquakes are created equal. The amount of death and destruction that one causes depend on many factors besides the Richter number. In many cases magnitude isn't even the most important factor. Earthquakes release different kinds of waves. A simplified way of looking at it is to think of them as vertical, horizontal, and compression waves. Once the waves get moving their destructiveness is strongly modified by geographical features like soil composition and coastlines. In Japan, the tsunami generated by the earthquake was hundreds of times more destructive than the shaking itself. Finally, and this might be most important in Virginia, building codes make a huge difference. The West Coast is young and most of our buildings were constructed under very strict codes that paid attention to the danger of earthquakes. In Virginia, no one expects an earthquake and many of the buildings in cities are older brick buildings (just about the worst place to be in an earthquake).

It's too soon to hear many details. I hope people are okay. I hope they learn the lesson that earthquakes can happen anywhere. I'm probably way too optimistic, but I hope some of our leaders will get the message that government regulations, like those building codes that limit tremor damage on the West Coast, can be a good thing. Proper regulations, properly enforced can save lives and save property (I'm not sure which is more important to our current leaders).

On Facebook, my Alaskan friends are already chiming in. I suppose you are a real West Coaster if your first reaction to an earthquake somewhere else is to check its Richter number and then snort, "Ha! You call that an earthquake? Let me tell you about earthquakes...."

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