Great article!

I grew up on the base of Mt. Diablo in Danville. I've been on the mountain many many times. Indeed the mountain is loaded with all kinds of ancient/prehistoric sea shells engrained in the soil from the time this land was under the sea.

This article is fascinating in more ways than one. In the past 10 years it has been amazing to observe the knowledge level of local residents about what the quake risk was really like for the San Ramon Valley. The area has only began to boom in the late 80s and before that earthquake hazards were always somebody else's problem. A big one would never happen there. Folks were still prepared for any strong shaking that might come off the San Andreas or Hayward (which indeed they did experience in Loma Prieta) but being on the epicenter-Nah!

Well the in 90 a swarm of quakes began right under the area. In a 2 week period the San Ramon Valley was rocked by 4 4+ quakes over 30 3s and countless 2s and 1s. I think it was then that people took notice that the Calaveras fault ran right under the area and scientists began warning that the main segment had been "locked" and that with the swarm we were seeing multiple little strands letting go.

Then just last year when the updated study came out showing the likelyhood by percent for a big one in the next 30 years, that segment of the Calaveras in Danville was given a probability for a 7+ quake in the next 30 years. And, in addition as pointed out above, the Mt. Diablo fault was revealed with a percent in its own right.

It is interesting, people are aware now. I think back as a kid how ignorant and bliss we all were going about our business and never thinking that right under our feet existed ticking time bombs. Now we know.