Hi All. I have been doing some looking around to see what kind of trouble I could get myself into and in doing so I found some data on the Pinole fault.

What I found is that the Pinole fault may very well be a thrust fault and its location between the southern end of the Rodgers Creek fault and the northern end of the Hayward fault may be the reason there is little to no movement along the southern section of the Rodgers Creek fault.

In the past the Pinole fault has been described as a possible step over between the Rodgers Creek and Hayward faults. The pattern of deformation indicates that the Pinole fault has a predominantly vertical component of motion and that the fault slip plane is blind or buried. Bedrock structure indicates that the Pinole fault is a thrust fault that dips to the east at a high angle. The recent faulting observed in the sediments of San Pablo Bay and the fault-related landforms observed along the Pinole Valley are consistent with deformation above a buried or ‘blind’ thrust fault. From the measured displacement of young geologic deposits, it has been calculated to have a minimum slip rate of 0.3 to 1.25 mm/yr. An estimated rupture length of 9 to 19 km indicates that the Pinole fault is capable of generating an earthquake of moment magnitude (Mw) 6.2 to 6.6.

If the Pinole fault is indeed a thrust fault then this could be the reason for the lack of creep within the southern section of the Rodgers Creek fault. The Pinole fault is acting as a wall preventing the creep from reaching that section of the Rodgers Creek fault. This may also be the reason we have seen quakes further north along the Rodgers Creek fault and also the reason we have seen quakes to each side of the Rodgers Creek fault the most recent of which was the Yountville quake. Take Care…Don in creepy town

• The Pinole Fault