Hi All. According to David Schwartz and others the Rodgers Creek Fault is the number one fault in the Bay Area to have a strong quake.

Topping a list of faults in the ten most damaging earthquake scenarios is the Rodgers Creek Fault, which is part of the Hayward Fault system. Rodgers Creek has a 15 percent probability of a magnitude 7.0 quake within the next 30 years.

"It's definitely going to happen because it's happened in the past," Schwartz said. "Take what you felt last night and go from a 4.3 to 6.7 or larger and that's a very sobering thought." He is talking about the M>4.3 quake in Santa Rosa on 05/25/2003.

The Rodgers Creek Fault starts in San Pablo Bay and runs north to Asti in the Alexander Valley. A strike-slip fault, it moves laterally, or sideways.

Seismologists believe the previous big one on the Rodgers Creek Fault was a magnitude 7.0 that probably occurred in the early to mid-1700s, based on trenching studies on Sonoma Mountain. There also is evidence of two other large earthquakes going back a total of 700 years or so, and they appear to occur about 230 years apart.

In Dec. of 1981 a number of seismologist were holding their breath. Starting on 12/13/1981 there was one M>2.3 quake. Then on 12/18/1981 there was M>3.4 quake. On 12/20/1981 there were 12 quakes with two of them having a magnitude of M>3.4 and one M>3.1. It started tapering off on 12/21/1981 with one small swarm again starting on 01/06/1982 and ending on 01/14/1982. Over a period of 12 years starting in 1982 there have been 7 quakes with 4 of them in 1994 and 3 of those were in Dec. 1994 which by the way was the last quake to be recorded in the area.

Starting in 1953 and ending in 1994 there have been 48 quakes with the greater majority of them occurring in 1981 with all of them in less then a 1-mile radius and is about 3 miles due east of Penngrove or about 5 miles NNE of Petaluma.

What does this all mean? I haven’t the foggiest idea, but with the number of M>4.0+ quakes we have had in the area over the past couple of years I can’t help but feel were getting a lot closer to having that large quake in the Bay Area. Take Care…Don in creepy town