The Big One

In Japan they call it "Tokai", and here in California we call it the "Big One". It's that massive earthquake that you're waiting for if you live in an earthquake prone region, and in California it would occur on the San Andreas fault.


The LA Times has an interesting article about seismologists that are creating underground images near the San Andreas fault. It looks like pretty intense field work. The scientists set off explosions along the fault and record the speed of seismic waves as they travel through the Earth's crust. The recordings are used to generate underground images. "So far, they had put out more than 4000 seismomemters, and the night crew had set off more than 100 explosions."

The more we know about the structure of the San Andreas fault, the more we can determine the impact of shaking from an earthquake like the Big One. Previous studies project 2000 deaths, 50,000 injuries, and $200 billion in damage from a 7.8 quake near the fault. That's much less than the recent quake and tsunami in Japan, but still significant.

I like this Google map of the San Andreas fault. It’s easy to zoom in and pan around on the fault. It’s right up against the base of the mountain ranges in some areas.

Also a detailed site about the San Andreas here.

While this fault is above ground, I wonder how they are studying rifts that are under the ocean...