[Godzilla]

use this USGS site, which will send me an eMail upon certain kinds of clustering activity, as well as quakes over a specified magnitude.

That fine and good, I visit the site weekly as well as the CA site (since I live here) daily. There are no discernable upticks in activity. On the contrary, things appear to be quite normal and in CA on the quiet side. So please expand upon your statement that activity levels have increased (or how ever you phrased it in your earlier post). Thanks.

[dr_pat]

Basin-and-Range extensional faulting covers western California (e.g. Death Valley), Nevada, Utah, New Mexico, and (fingers) up into the Snake River plain. Clusters of small quakes (1-2.5 Richter) were reported following the 9.0 temblor off Sumatra's coast on Boxing Day, peaking at times concordant with the expected arrival times for S, P and Rayleigh waves.

The frequency may be ultra-sub-sonic, but the Earth rang like a bell.