Somewhere I have done a huge thing on blind thrust supershear earthquakes. I even did a wikipedia on it. The whole area is under compression because of mountain building. Then they have these lovely valleys where everybody likes to settle. But what are they really? They are the scars of old thrust faults. Each one goes every few hundred years, but there are a lot of them. The PGV is record-breaking, if somebody could record it, probably 2 m/s or more.