![]() Sediment in the outer shelf of California's State Waters is rippled, indicating some mobility. Sediment is observed offshore in the central part of the map area, in the shelter of the headlands north of the east strand of the San Gregorio Fault (also called the Coastways Fault) around Miramontes Point (about 5 km north of the map area) and also on the outer half of the California's State Waters shelf in the south where depths exceed 40 m. The regional uplift in this map area has caused relatively shallow water depths within California's State Waters and, thus, little accommodation space for sediment accumulation. In the south, headlands near Pescadero Point have been uplifted by motion along the west strand of the San Gregorio Fault (also called the Frijoles Fault), which separates rocks of the Pigeon Point Formation south of the fault from rocks of the Purisima Formation north of the fault. Coastal promontories in the northern and southern parts of the map area are the result of right-lateral motion on strands of the San Gregorio Fault system. The coastal area consists of high coastal bluffs and vertical sea cliffs. A westward bend in the San Andreas Fault Zone, southeast of the map area, coupled with right-lateral movement along the San Gregorio Fault system have caused regional folding and uplift. The coastal geomorphology is controlled by late Pleistocene and Holocene slip in the San Gregorio Fault system. The hilly coastal area is virtually undeveloped grazing land for sheep and cattle. No harbor facilities are within the Offshore of San Gregorio map area. Both communities are situated inland of state beaches that share their names. The nearest significant onshore cultural centers in the map area are San Gregorio and Pescadero, both unincorporated communities with populations well under 1,000. The Santa Cruz Mountains lie between the San Andreas Fault Zone and the San Gregorio Fault system. The map area lies offshore of the Santa Cruz Mountains, part of the northwest-trending Coast Ranges that run roughly parallel to the San Andreas Fault Zone. The Offshore of San Gregorio map area is located in northern California, on the Pacific coast of the San Francisco Peninsula about 50 kilometers south of the Golden Gate. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within the 3-nautical-mile limit of California's State Waters.
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