Faults--Offshore Pigeon Point, California

This part of DS 781 presents data for the faults for the geologic and geomorphic map of the Offshore Pigeon Point map area, California. The vector data file is included in "Faults_OffshorePigeonPoint.zip," which is accessible from http://dx.doi.org/10.5066/F7513W80
The offshore Pigeon Point map area lies about 15 to 25 km southwest of the San Andreas Fault, the dominant structure in the distributed transform boundary between the North American and Pacific plates. The map area straddles the right-lateral Pigeon Point Fault zone, a prominent structure west of the San Andreas Fault in the broader San Andreas Fault system. The Pigeon Point Fault zone occurs predominantly in the offshore and extends 400 km from Point Conception on the south to Bolinas and Point Reyes on the north (Dickinson and others, 2005), coming onland at coastal promontories such as Pescadero Point in the map area and Pillar Point, a few km north of Half Moon Bay.
In the offshore, the Pigeon Point Fault system forms a distributed shear zone about 2 to 4 km wide that includes two main diverging fault strands. The western strand (also known as the Frijoles Fault) extends offshore from Pescadero Point. The eastern strand (also known as the Coastways Fault or Seal Cove Fault), is mostly onshore in this map area. Cumulative lateral slip on the Pigeon Point Fault zone is thought to range from 4 to 10 mm/yr in this region (U.S. Geological Survey, 2010). The western strand of the Pigeon Point Fault zone (i.e., Frijoles Fault) forms the eastern boundary of the Pigeon Point high.
Faults were primarily mapped by interpretation of seismic reflection profile data (see OFR 2013-1071). The seismic reflection profiles were collected between 2007 and 2010.
References Cited
Dickinson, W.R., Ducea, M., Rosenberg, L.I., Greene, H.G., Graham, S.A., Clark, J.C., Weber, G.E., Kidder, S., Ernst, W.G., and Brabb, E.E., 2005, Net dextral slip, Neogene Pigeon Point-Hosgri fault zone, coastal California: Geologic evidence and tectonic implications: Geological Society of America Special Paper 391, 43 p.