Saturday, February 9, 2013

Columbia M7.0 earthquake

This is even deeper, supposedly, than the M7 under Northern Japan.  Thus, we expect almost no PGV at surface.  This is on the subducting slab, but right about where there is a big curve.

You'll notice the character of the subduction changes at this point.  We are not surprised then, that this is not a perfect downthust, as with Japan, but a rather cute strike-slip.  This indicates shear stresses.

I, for one, am surprised that we do have a clean strike-slip, since it is very deep, and these things are not good in 3 dimensions, you usually need to have the surface involved to accommodate the motions.

Second Thoughts:  The required free surfaces can be the decoupled top and bottom of the slab, so I'm ok with all this now.  :)

No comments: