Hi All. I owe Petra an apology so let me start by saying, “I apologize Petra. Please forgive my comments which are based on not understanding” Yesterday while we were talking about this and that she told me she just heard this sound in her right ear. She told me there would be an earthquake north of where we were. I told her to clear her head by blowing her nose and then swallowing real hard. This would make the noise stop. Fortunately for me she knows my feelings on this so I wasn’t clobbered. My problem is that I have a hard time in understanding the sound she hears. I have a ringing in my ears all the time. Being near to many gun shots, explosions and jet aircraft caused mine.

Anyway low and behold this morning I see there has been a small swarm of quakes just north of where she lives. I got to thinking about what she said. She has taken me a number of times to the Rodgers Creek Fault so I thought I would do some research on that fault and what I found was very interesting to say the least.

The Rodgers Creek fault runs approximately from the San Francisco Bay up through or close to the towns or cities of Sonoma, Petaluma, Cotati, Rohnert Park, Sebastopol, and Santa Rosa. Running along the west side of Sonoma Mountain it (the Rodgers Creek fault) runs about six miles from downtown Petaluma and closer than that to Rohnert Park before it runs into Santa Rosa. The Rodgers Creek fault is sometimes considered an extension of the Hayward fault running through Hayward, Oakland, Berkeley, etc.
The Healdsburg fault is an extension of the Rodgers Creek fault and runs north of Santa Rosa through Healdsburg. Extensions of it, along with neighboring faults, pass through the Alexander Valley up by Cloverdale, the northernmost city in the county. Cities located along the Healdsburg fault and these neighboring faults include Windsor, Healdsburg, Geyserville, and Cloverdale.

The Rogers Creek Fault is thought to be able to have a quake up to 7.0Ml on it. This estimate is based in part on the 1898 magnitude 6.5 Mare Island earthquake and the length of the fault, which is 63Km long. It is felt that a 43Km rupture of the fault would produce a 7.0Ml quake.

Now this small swarm may not be a precursor to a much larger quake, but should be a wake up call. Somehow I feel that we have already received the wake up call. The most recent Napa quake may have been that wake up call. If a quake that size was able to occur where a fault is not know (they are still out to lunch on the location) then that is telling me there is sufficient strain in the area to bring about a much larger quake particularly on a fault that is felt capable of having a quake of 7.0Ml.

Again. Please except my apology Petra and thanks for not clobbering me. Take Care…Don in creepy town.