Wednesday, January 28, 2009

Famous Earthquakes: Coalinga 1983

This was the year I got married, and the day before, I experienced the Adirondacks earthquake. That earthquake was a great waker-upper, but we didn't learn much from it. Now, Coalinga, that was a beauty!

On the surface, it was a typical disaster, with lots of buildings destroyed. Ground motions were estimated at 20-60%g by those nasty people who only think of PGA! I estimate the PGV at about 0.5 to 1 m/s. It's something that would knock you off your feet on the soft ground. It was an M6.7 earthquake, fairly close.

But the detailed study showed that only the usual suspects (loose brick) were destroyed! Anything that had the tiniest thought of resisting earthquakes did quite well. This was one of the major earthquakes that led the new discipline of 'Seismic Experience', which, as I have told you before, has been buried by self-interest groups. As usual, they found that pipes were never damaged.

The aftershocks were notable, mainly that there was an M6.0 right under a steam plant. Not a speck of damage! This earthquake alone convinced me that all those seismic analysis people were quacks! But they have the big money, and the next nuclear reactor will cost a billion dollars more because of it.


Anonymous said...

I'd never heard of the lack of damage in Coalinga before. Interesting, especially about the steam plant.

Harold Asmis said...

From EQE "Well designed and constructed structures and most steel framed buildings were generally undamaged."

Silver Fox said...

I had been working in the area just the year before, and had even stayed at Coalinga (pronounced locally as Cuh-LING-ga, run-it-together-real-fast) a few nights. A good portion of the town - the old downtown part common in most western towns - consisted of way-old (that's a technical term) brick buildings, and so the external damage looked quite impressive. Don't know what happened to the newer motel, probably not as much.