Hi Bob,

you are probably correct that they were removed. What is left is around the geothermal plant, although this is from memory; I'm not checking. They withdraw and inject a lot of fluid, and this is liable to trigger shallow quakes; this must be known, but I'm just using logic. The crust is thin and hot in that area so the base of most quakes may be shallow; again guessing, but 10 km vs. 15 or 20 km elsewhere along the San Andreas Fault.
Chris