Monday, June 16, 2008

BSSA June 2008

I got the big thick journal the other day. This is a really good one for me, filled with all the things I love: super shear rupture, stress disturbance, triggering, etc. I dislike the horrible complex calculations of ground motion, since I think they far beyond the true uncertainties.

I start with a great paper, which describes the world-wide stress disturbance of a giant earthquake. Anyone who has done discreet modeling with sliding blocks knows that perturbations go way farther than expected, because the whole thing is a non-linear mess! And so it is with the earth.

The basic hypothesis involves this fact and looks for seismicity changes following giant earthquakes. It found a significant effect, especially when you sort out areas that would become more unstable by the stress disturbance (some areas would become more stable).

They used past data to refine the method, but then did a brave thing. They have calculated the 'weather report' of earthquakes, disturbed by the giant M9 tsunami Sumatra quake.

There is a good chance that all these red areas will be lit up like Christmas trees in the next few years. I haven't really checked whether China and Japan fit this, since you have to look at this stupid map with a magnifying glass, and there are multiple mechanisms within each zone.

So if you're wondering if there are a lot more earthquakes recently, maybe you're right! And maybe the Toronto area got a good whump, so crazy Harold will finally be vindicated! Muhaha!


Silver Fox said...

Interesting article. Makes me go hmmm...

Harold Asmis said...

Me too! hmmmmmmm.