Hi All,

Don and I have taken quite an interest in these two small earthquakes, as it appears there hasn't been any activity in this area for as long as we two can remember.

Our joint hypothesis on these two at the moment is that they are yet another sign that the Rodgers Creek Fault is locked so tight that the stress is showing up in outlying area's.

If you'll notice the most southern of the two quakes is due west of Healdsburg, a place which has had a lot of small earthquakes in the past few years.

So the question remains, how much longer can the Rodgers Creek Fault stand still when there is data supporting the Hayward fault that indicates it is moving at a northerly pace and is not locked? Where is that energy going? From our perspective it is showing up on both sides of the Rodgers Creek fault. A good indicator was the Bennett Valley quake in 1999, the Yountville quake in 2000, and the latest small swarm just east of the RCF a couple of weeks ago. So, perhaps this off shore activity we are seeing now is further evidence of our hypothesis?

Does anyone else have any thoughts on this? We'd appreciate hearing from you.

Petra & Don

• The Seismic Safety Zone