re: #227 Love-Child of Cassandra and Sisyphus

An item Twitter is pushing is the study on San Andreas fault quakes. The Twitter splash language:

Very misleading.

San Andreas fault quakes are due to slippage along the fault. While these can be quite large, they are not “megaquakes”.

The really big quakes, like the Honshu quake that cause such damage in Japan a few years ago, are due to plate subduction. There is a risk of this in the US: in the Pacific northwest and in Alaska.

But not in California.

So yes, a large earthquake in California, say an 8.0, will cause a lot of damage. But top of the scale quakes, close to 9.0, only happen in the subduction zones.

Ding! Ding! Ding!

Look north to the Cascade Fault Zone. If that that thing ruptures, it’ll be an 800-mile long subducted ledge of continental crust that is going to jump up 120’ almost instantaneously. Mayhem ensues.