Wednesday, February 6, 2013

Aftershocks fill in M8 earthquake fault zone

Good old aftershocks.  You can always count on them to define your actual fault zone.  That's because the fault ruptures unevenly, and these smaller quakes smooth off the rough spots.  If you wait too long, then there is a chance of the next fault rupture down the line.

This is the same picture, but in more detail.  We can that the earthquake totally shifted a corner.  Very weird.  But I am surprised at the smaller fault area for an M8, which implies high stresses and more intensity.  I doubt that that there were any strong ground motion instruments, but those little unnamed islands on the corner must have got hit with something powerful.

Now, in this complex area, I was thinking that the M8 is as big as they're going to get, but it was a very small corner.  The two sides can easily rupture to full M9's as they appear smooth enough.  Then we'll see a big regional tsunami, but perhaps not for many years.  In the meantime, don't get plastered at a beach party there, and sleep it off on the beach!

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