Hello Chris,

In the case of Berkeley, I have looked at the directivity plots of Alum Rock, Piedmont, and two quakes in Glen Ellen. What I see on the fault map now is a lack of activity, one of my hypothetical factors for vulnerability. Berkeley has been hitting off and on over the last year, and I think it is ripe for a light quake now...My guess is that the directivity plots of the latest light quakes in the region have dilated that particular section of the Hayward Fault, and the creep rate will supply the needed re-compression to overcome a small asperity which must exist there. This is hypothetical, and the timing is guess work. I'm not forecasting a big one, although that could happen, I suppose. I have no set algorithm for it. It is dynamic, not static.

Glen