Wednesday, May 7, 2008

Virginia Earthquake

My mom called me yesterday to gloat about the earthquake in Northern Virginia. She seemed so hopeful that she could tell me before I'd checked the USGS page and seen it for myself (which, in fact, I hadn't, since I was in rehearsal all afternoon), and so glad that she could lord it over me that there haven't been any noticeable quakes in Virginia while I was there.
"So, did you feel it?" I asked.
"No," she told me.
"And how big are we talking?"

As far as I was concerned, she lost all the gloating credibility at letting on that she didn't feel it, but the fact that people were feeling this 1.8 (it's since been upgraded to 2.0) at all really did surprise me. I didn't quite believe mom that people had actually felt it until I could get to the USGS site. In California, people don't feel the 1.8s. I'm not sure if it's solely related to the heavily fragmented and faulted nature of the rock here (versus the less pulverized stuff in Virginia) stopping propagation, or if there's also a factor of Californians being too jaded to small quakes to notice them anymore (versus people east of the Rockies who are maybe still twitchy about the 18 April quake in Illinois). Either way, and no matter how shallow the Virginia quake was (only 6 km down), 1.8 (or 2.0) is pretty small. I am impressed by how widely it made itself known!
The smallest earthquake I've ever felt (and, incidentally, the first I ever felt) was a magnitude 2.9. For all I get excited when I feel one that beats out my previous largest (which is, to date, 4.7), now I'm curious to see if I can beat my previous low in terms of magnitudes I'll feel.
(Speaking of feeling low-magnitude quakes, The Onion has an article on the matter... Also, I seem to like parentheses today.)

The USGS site also revealed that the epicenter of this quake was less than ten miles from the house where I grew up, and pretty much directly under my brother's school. There have been plenty closer than ten miles to where I live now, but there is no weirdness factor in that for California. "Right under my house" is not a place I like there to be earthquake hypocenters regardless of state, but "right under my Virginia" would have an extremely high magnitude on the weirdness scale.

Callan and Tuff Cookie have already written more scientifically and eloquently about yesterday's Virginia earthquake. Read their posts if you haven't already!

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