Wednesday, March 16, 2011

Japan Earthquake - Detailed Strong Ground Motion


Now, this is the good technical stuff, which is all I'm sticking to right now.  That other stuff is way too depressing, and we all know I don't handle 'depressing' very well.

This shows the huge, factor of 10, difference in the PGV at the same distance from the fault.  Usually, when you see this, you must assume the lower is on firm ground, and the upper is on swamp.  We didn't have this sort of variation with Chile.  I now make the big assumption that the nuclear plants were knocked out with a very low value of 10 cm/s to the reactor base, and the generators (which are always on swamp) were knocked out by 100cm/s.  I don't go with the thought that everything was perfectly ok before the tsunami hit.

This makes Japanese reactors more fragile than condo towers!

Now that we have the strong ground motion, we can have fun looking at the rupture dynamics.

This was a very clean rupture, with a little blip on the side.  Most magnificent!

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