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1868 Hayward Earthquake Alliance

Activities & Events

Geology and Tectonics of the San Francisco North Bay Area

California State University, East Bay, Vector Engineering and BACE Geotechnical


James Allen, CSU East Bay, Earth and Environmental Sciences
Peter Holland, Vector Engineering; and James Wilen, BACE Geotechnical
James Wilen, BACE Geotechnical

During this field trip, we will make 5 stops:

  1. The Steinbeck Ranch, where we will examine the typical lithology and stratification of the Wilson Grove Formation. The underlying Franciscan Complex, Tolay Volcanics, as well as the interbedded Roblar Tuff (one of the best marker beds in the formation) will be observed at this stop.
  2. Stony Point Rock Quarry, where the lower and middle members of the Petaluma Formation, as well as underlying and interbedded Tolay Volcanics will be examined. Particular attention will be paid to the gravel composition of the middle Petaluma Formation.
  3. Stony Point Road, north of the Stony Point Rock Quarry, where a road cut exposure of the upper member of the PF will be examined. The gravel composition of the upper member will be discussed.
  4. Taylor Mountain landslide, where the head scarp exposes Tolay Volcanics thrust over the Petaluma Formation. Active landslide features will also be observed.
  5. Matanzas Creek in Bennett Valley, where we will observe the Petaluma Formation east of the Rodgers Creek fault and compare it with the Petaluma Formation west of the Rodgers Creek fault.


Saturday, June 14, 2008 at 9 AM


Southbound Park and Ride Lot at Highway 101 and Rohnert Park Expressway in Rohnert Park


Slip and deformation along the Hayward Fault and other East Bay Faults, and their North Bay equivalents.


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