Sunday, February 15, 2009
Famous Earthquakes - Kobe 1995
With this mid-size earthquake (M6.7), we learned the true power of the urban earthquake, and something more. After the Armenia earthquake, and then this one, I became convinced there was a bit more to Magnitude, when it came to damage.
The fault that whacked Kobe was way off the beaten path. For years, Japan was only expecting earthquakes from these monstrous faults. Who would expect an interior fault? But this was a thrust fault and it did something very bizarre.
Digression: I'm getting all this from the EQE report! I finally found them all right here!
Now, I can only find the peak accelerations, which were around 0.6 g, but somewhere they must have the PGV's. Looking at the damage, and the videos, I think the PGV hit 1-2 m/s, which is huge! All this from an M6.7
But this was no ordinary earthquake, this was a 'super-pulse', where a high velocity pulse runs up the fault, and smashes the surface! Of course, the soft ground didn't help much.
Since all the water mains were destroyed, there were huge fires.
As always in an EQE report, they looked at things which should have been damaged, but weren't. You never find that in a 'standard' earthquake report. Well-anchored pumping and industrial facilities were not damaged. Well-designed building out of the main swamp were also not damaged.