Hi Chris. Thank you. You have given me at least a month worth of reading material. I found other links covering pretty much the same thing.

What I found interesting was what was said about the Loma Prieta quake. Even though the Loma Prieta quake occurred in the area of the 1906 rupture the rupture was less in this area then in the segment of the fault north of Black Mountain. In the earthquake of April 1906 the displacement was up to 21 feet in the Point Reyes area, the largest surface displacement ever recorded. Along the San Francisco Peninsula section of fault the displacement was less, and it dropped yet again South of Black Mountain. There are some who think that this might have happened because the moving rupture partially dissipated when it hit the obstruction. The fault makes a jog of about 9 degrees around the mountain.

What makes the fault real interesting in this area is that south of Black Mountain you can see indications of compression while at the same time you can see signs of rifting north of the mountain. In regards to a major quake on the San Andreas Fault the most probable location is the Crystals Springs Lake area as this area is almost completely devoid of quakes. In other words a “seismic gap” much in the same as the area of the Loma Prieta quake. This area by the way is south of Black Mountain, but not by very much.

There are other faults in the Bay Area that could produce a quake up to M>7.5, but the one considered most likely to is the Rodgers Creek Fault. The segment of the fault between Santa Rosa and San Pablo Bay isn’t showing any creep. One area of interest is located just to the northeast of Petaluma in that this area in the past has had some small swarms of quakes indicating that it may be an area of weakness. I have been told that one of the things to watch for is quakes in the M>5.0 range and a little larger about 5 miles or less to the east of the fault it could be near breaking. Not exactly sure as to why, but have a feeling it may be along the same lines as what was seen before the Loma Prieta quake. Of course that’s not to say that the quake couldn’t occur out of the blue.

I have a feeling the next couple of years are going to be real interesting. Take Care…Don in creepy town