Hi Lowell. I have been busier then a one legged man at a butt kicking contest. I hate to see what my phone bill will look like next month. I have been trying to find someone who has first hand knowledge of the Pinole fault. No luck so far.

The quake near Pacifica is associated with the San Andreas fault. There have been a number of quakes in and around this area. There have also been a number of quakes near the middle of the entrance to the San Francisco Bay.

I don’t think there is a connection to the quake in the San Pablo Bay, but I do feel that what triggered the quake near Pacifica could also trigger another quake on the Pinole fault. It could also trigger a quake on the Rodgers Creek fault. My forecast was for 09/07/2001 for Novato. We still have one more day to go. Based on the data for the Bay Area I don’t see a major quake occurring on the Hayward at this time. However that does not rule out any of the other faults in the area.

So far this is the only good description of the Pinole fault that I could find. Take Care…Don in creepy town

The north-northeast-striking Pinole fault is located within what has become known as the “East Bay Fold and Thrust Belt”, located between the Hayward-Rodgers Creek and Calaveras-Concord-Green Valley fault systems, both of which are northwest-striking, right-lateral strike-slip faults of the San Andreas system. Each of these fault systems has experienced coseismic rupture during historic time; a ML 6.8 earthquake occurred on the southern Hayward fault on 21 October 1868 and a ML 5.6 on 4 July 1861 on the Calaveras fault. Previous workers have mapped this region as a series of north-northeast-trending folds and both west and east verging folds and thrust faults. Cenozoic sediments are involved in the folding and faulting of this region, demonstrating significant compressional deformation across this area during Cenozoic time. Geodetic measurements and focal plane mechanisms for recent earthquakes indicate that contemporary deformation in this area is dominated by right-lateral strike-slip faulting. The majority of this deformation is accommodated along the larger strike-slip faults. The role of secondary faults in the contemporary deformation of the East Bay and how they interact with the primary faults of the San Andreas systems is poorly known.

In addition to the clear evidence of deformation within late Quaternary deposits in San Pablo Bay, this appears to indicate that the Pinole fault is active and plays a part in accommodating strain in the East Bay Hills region. The pattern of deformation observed in marine seismic records, along with the geomorphic evidence recorded onshore indicates that the Pinole fault has a predominantly vertical component of motion and that the fault slip plane is blind or buried.

Based on the displacement of latest Pleistocene and Holocene deposits, a minimum slip rate of 0.3 to 1.25 mm/yr is calculated for the Pinole fault. An estimated rupture length of 9 to 19 km indicates that the Pinole fault is capable of generating an earthquake of Mw 6.2 to 6.6.

• Pinole Fault Study