Hi All. Thought I would refresh everyone’s memory about what is known and isn’t known about the southern segment of Rodgers Creek fault.

For the most part there isn’t any movement along to this segment of the fault. What quakes have occurred have been far and few between.

On 12/20/1981 there were 15 small quakes in the area of 38.3002N/122.6092W. This is about 3 miles east of Petaluma. These quakes were located west of the Rodgers Creek fault and as the fault dips to the west in this area it is more then likely these were associated with the fault.

The Bennett Valley quake of 1999 was located east of the fault. The motion of this quake indicates that it occurred on a reverse fault. The “moment tensor solution” indicates almost “pure thrust” so more then likely it didn’t occur on the Rodgers Creek fault.

Three trenches have been dug across the fault. The last known major quake is thought to have been around 1600. There are some though who feel that the Mare Island quake in the late 1800s may have occurred on the fault. There is also a chance that the Pinole thrust fault in San Pablo Bay may have been the source of this quake. Some of you may remember the forecast I made for Novato on 09/04/2001. The quakes that occurred over a period a couple of weeks following that forecast were most likely on the Pinole thrust fault. The forecast epicenter was less than 10 km from the located epicenter and occurred about 10 hours after the posted forecast. It was my long shot for the week and wouldn’t you know it it came in on time.

USGS has ranked the Rodgers Creek fault as the number one fault for the next major quake in the Bay Area. This doesn’t mean that the next major quake will be on this fault, but that there is a greater probability that it will.

I still have lots of Corona Beer, but will have to stock up on some onions and garlic. Take Care…Don in creepy town