Hi All. By now I suspect that some of you if not all of you are getting a little tired reading about the Rodgers Creek Fault. Just bear with me a little longer as I have just about picked the information bush clean.

The Rodgers Creek Fault trends northwestward from San Pablo Bay up through Santa Rosa and joins the potentially active Healdsburg fault in the town of Healdsburg. The fault runs for 39 miles and is contained entirely within Sonoma County. The largest recorded earth- quake was a Richter magnitude 5.7 in 1969. The Rodgers Creek fault is estimated to be capable of generating a maximum earthquake of Richter magnitude 7.0. The trend of the Healdsburg-Rodgers Creek and Hayward faults are similar. suggesting that they may be related. The Rodgers Creek fault is thought to be capable of generating ground shaking in Contra Costa County that would reach very strong levels. This is because of the alluvial fans of which most of the valley is made up of. It is felt that Marin County would be the worst in regards to slides. I know that the parts of Sonoma County I have seen I don’t think they would fair much better in the slide department.

The Maacama Fault is just to the east of the Rodgers Creek Fault. There are several small faults in between the two, but there doesn’t appear to be any step over.

All of the most recent activity on the fault has been from the little town of Penngrove northward. From Penngrove south there has been no movement that can be said to be associated with fault. There have been 4 very small quakes in the past, but that has been the extent of activity south of Penngrove. There may have been more, but at present I’m not aware of them.

It is within this section of the fault that Petra has her study area. When she first showed it to me the first thought that came to mind was that this is a slide looking for a place to happen. There are sag ponds all along the fault so it’s not hard to trace if you can gain a high vantage point so that you can look down upon it.

If I were an earthquake looking for a place to occur this would be it. I would sure take a lot of people by surprise. USGS gives it a 32% chance of having a major quake in the next 30 years. That makes the Rodgers Creek Fault the number one fault to watch. Take Care…Don in creepy town.