Boom This Unstable Earth
posted by August 21 at 13:03 PM
onWe learn geology the morning after the earthquake, on ghastly diagrams of cloven mountains, upheaved plains, and the dry bed of the sea.
(Ralph Waldo Emerson)
The largest earthquakes of the last week (count: 181).
The largest earthquakes of the last week in North America (count: 131).
The largest earthquakes of the last week in the Pacific Northwest (count: 27).
From the always-fun-to-refresh USGS earthquake charts.
(Thanks to Slog tipper Kevin S.)
This is the reason that normal, red-blooded, commonsensical Americans have six or seven back-up homes.
Isn't it always a good thing that we have a lot of tiny earthquakes to relieve the pressure on the fault lines? Or am I reciting faulty made up scientific pap here? Not being a geologist, I wouldn't know the difference.
Hmm, I believe the same thing as PopTart. Is I wrong?
Back to Pangia!
@2 & 3:
It's been awhile since geology class, but here's my (perhaps mistaken) take on the small tremor thing y'all brought up. Sure, it's nice and all, and it does relieve some pressure on fault systems, but not enough to prevent moderate or major quakes. Not NEARLY enough. At best, they slightly delay the inevitable.
What's "best" (relatively speaking) is a fault system that has these tiny quakes that no one feels (most fault systems have these), coupled with moderate/semimajor burps that crop up every few decades or once a century. Those moderate quakes, while destructive, really help draw down the pressure, potentially dampening "the big one" (a quake that will flatten nearly everything and potentially cause a huge loss of life). Oddly, think Southern California here for a system with minor/semimajor burps... as I understand it, the fault systems there are prone to many moderate quakes, which makes "the big one" much less likely in our lifetime (or simply causes "the big one" to be much less big).
Unfortunately, the fault systems closer to the bay area and up here in Seattle (the Seattle fault runs beneath downtown and Pioneer Square), are much less likely to produce burps. Pressure builds and builds and builds until "the big one" occurs. I don't know why this is the case. I'm just told this it the trend based on looking at past quakes in this are.
But, I could be (hell, I likely am) wrong here. It's been awhile since geology class, and I was never interested in earthquakes.
I'm so glad someone else appreciates the USGS earthquake maps, which are actually one of my secret nerd obsessions. When I boot up my computer in the morning, the NW map is the first thing I check.
This is the first site I checked after the Nisqually quake. Basically there was a big red square over Western Washington. It is a good URL to remember the next time we get a shaker. It autocalculates the magnitude and epicenter.
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