Hi All. This is taken in part from studies being done by Jon S. Galehouse Department of Geosciences San Francisco State University San Francisco, California 94132 of the various faults in the Bay Area.

“We measured a site (16) on the Rodgers Creek fault in Santa Rosa from August 1980 until we had to abandon it for logistical reasons in January 1986. During these 5.4 years of measurements, no significant surface slip occurred and we concluded that the Rodgers Creek fault was not creeping at this site.”

“In September 1986, we established Site 21 on the Rodgers Creek fault near Penngrove (see Figure 1). The average at Site 21 has been about 2 mm/yr right-laterally for the past nine years. However, there appears to be a lot of surface "noise" at this site and in mid-1993, we discovered that one of our triangulation points had become unstable. We have since reconfigured our measurement array but at present, it is difficult to know whether or not the Rodgers Creek fault is really creeping slowly or whether the low rate is due to nontectonic reasons. The LPEQ (Loma Prieta Earthquake) does not appear to have had any effect on the Rodgers Creek fault at Site 21.”

The interesting thing about the LPEQ is that San Francisco State personnel had been measuring horizontal slip at two sites on the Calaveras fault in the Hollister area for 16 years. Slip at both sites has been episodic with intervals of relatively rapid right slip typically lasting a couple months or less alternating with longer periods of time when little net slip occurs. The LPEQ occurred during an interval of slower movement that had persisted for about a year at Site 4. The earthquake apparently triggered up to 14 mm of right slip at Seventh Street.

In August of this year Petra took me to her study area, as she prefers to call it. This area is near Penngrove. I was impressed when I first saw the area. Everything gave the indication that in the distant past this area had been subjected to some impressive tectonic forces as well as volcanic forces. As Petra pointed out to me the area was littered with volcanic bombs. I must admit I was also impressed with the knowledge this weird lady displayed about this area. She may be a blonde, but a dumb one she is not. No disrespect intended against blondes. Just weird, which makes me just as weird as I volunteered to work with her.

The thing I noticed was that the whole area gave the appearance of a slide looking for a place to happen. This may account for the surface noise talked about in the above article. For the sake of starting an argument lets say that what they were seeing was surface noise and not movement of the fault. This would indicate that the fault in this area is locked and therefore could be the location, or any portion of the fault south of there for the next 7.0+ quake. This also happens to be the portion of the fault that Petra is uncomfortable with. She has given me a time frame, which for what it’s worth I agree with. With the recent quakes that have centered north and east of here I would have to say that this may very well be the next location a large quake. Time will tell. Take Care…Don in creepy town.