Eastern Earthquake Provides Useful Warning

It’s great to see the widespread coverage of the eastern earthquake, despite its modest strength (although I’m not sure some of the underwhelming video coverage was worthwhile).

The 5.8-magnitude quake, centered in Virginia 83 miles southwest of Washington, D.C., is a reminder of the importance of factoring in shaking in the design of buildings and important installations like nuclear power plants.

USGS A 6.8-magnitude earthquake in 1895, centered in Charleston, Mo., caused widespread damage and was felt from Louisiana to western New York

While rare, eastern earthquakes can be dangerous, most notably those triggered in the New Madrid seismic zone along the Mississippi River valley.

One issue is that the geology of the east is more favorable to transmitting earthquake energy long distances, as described this way by the United States Geological Survey in context provided for the Virginia quake:

East of the Rockies, an earthquake can be felt over an area as much as ten times larger than a similar magnitude earthquake on the west coast.

This year is the bicentennial of the great New Madrid earthquakes of 1811-12, an anniversary marked by federal disaster agencies in May with an exercise responding to a simulated major quake in the region.

Although some earth scientists in the region, notably Seth Stein of Northwestern University, say the threat of a catastrophic repeat is overblown, that’s no reason not to take shaking into consideration in designing structures or securing items in a house or business to limit losses if the worst happens.

via dotearth.blogs.nytimes.com