Saturday, January 30, 2016
Tiny M7 up near Alaska
These are the big subduction zones of the world. Here, an M7 is like a 4 to us. A clean, gently curving zone probably means a 9+ every 800 years or so, just like Japan. This is at a weird corner, with the upper zone very curved. Thus, that lower zone could probably get a 9.2 or 9.3 (two to three times longer than a 9), but the upper zone is probably limited to 8's. The zone straightens out towards Alaska and we know that can cough up 9's.
Anyway, this only matters for tsunamis, since they are in the middle of nowhere, and the ground motion saturates at 8 or so. A big one on the lower zone beams right at the NA west coast, but you would get hours of warning. Might even be long enough to evacuate some of the coasts. :) But this earthquake gives no indication as to future events, it's just cute. :)
ps. Basin Amplification
We don't know the units, nor why it is showing standing waves. Nevertheless, you don't don't want to be there if there is a 'real' earthquake.
More details - http://www.giseis.alaska.edu/input/carl/research/earthquakes/iniskin.html
There is a neat movie, and the plot is velocity showing standing waves at each time step. If you ran the whole thing, you would get PGV which should line up with Intensity. This is great work! I love it!
pps. I hope he gets some readings. The Polaris northern stations take a holiday in January when it goes to 40 below and there is no sunshine. Bad for solar cells. We need 'Martian' nuclear batteries, which can also double up as footwarmers. :)