Hi Chris. The M>3.0 quake east of Clear Lake caught my interest in that there are no faults shown on the earthquake map in the immediate area.

I got my fault map out and found that there are at least 5 faults in that area. They are all designated as having activity in the last 1.6 million years. As of right now I have been able to find some data for only one of the faults. It is the Hunting Creek/Berryessa Fault. It starts at 38.45N/122.20W and ends at 38.93N/122.50W. The USGS fault listing shows that it can have a quake up to M>6.0. The M>3.0 quake appears to be a little to the north and east of the northern end of the fault. The location of the quake in the ANSS catalog is shown at 39.0325N -122.4423W

Just in case anyone is interested the names of the other faults is Wilson, Cross Spring, Ellis, and Coast Range. These faults are all located just to the east of Clear Lake.

Using the ANSS catalog with a radius of 5miles I found 16 quakes have occurred in the area from 1951 to present time. The strongest quake was a 4.2Md that occurred on 09/24/1984 at 38.9777N -122.4900W. Take Care…Don in creepy town