This map shows the areas of Santa Cruz County where firearm discharge is prohibited as described by section 8.28.030 of the Santa Cruz County Code.

This polygon shapefile represents land use and land cover for the Pajaro River and San Benito River Watershed in San Benito, Santa Clara, and Santa Cruz counties of California for 2005. This shapefile was extracted from a generalized land use/land cover database of the Salinas-Pajaro region. Map unit categories were based on a modified Anderson Level II hierarchy. Mapping generally adhered to a 0.5 acre Minimum Mapping Unit (MMU) for riparian and agriculture types and 1 acre MMU for all upland, urban, or other land use types. Vegetation percent cover classes were assigned to the tree and shrub layers for each stand. Herbaceous vegetation was not assigned a cover class. All density values are measured in absolute cover, not relative cover. If tree cover is equal to or greater than 40% then the shrub cover is assigned a Not Assessed value of 9. The minimum mapping unit (MMU) resolution size of the land use/land cover polygons is twofold. In the intense agricultural region and for wetland and riparian areas the polygons have a 0.5 acre MMU. In the remainder of the study area, composed of non-agricultural areas, upland vegetation, and urban areas, the MMU is 1 acre. For thin linear-shaped polygons the MMU for width is one half the width of a full MMU square. Exceptions to the MMU guidance are noted in further criteria below. Because of the agricultural emphasis of the project, large urban developed areas, such as cities, towns, and villages, were not typically further subdivided other than for agricultural uses within their extents. The MMU size for these agricultural uses within urban areas is 0.5 acres. As noted above, the study area overlaps with the 2005 mapping of the Salinas River and San Benito river major riparian corridors that Aerial Information Systems, Inc. conducted for the Nature Conservancy. The MMU for the original projects was <0.5 acres. Where those units had not changed for 2005 and 2012 mapping, the map units were kept at the original polygon size. The 0.5 acre MMU is used for new mapping of riparian and wetland map units. Other Mapping Criteria includes photo interpretation of land cover is based on state-wide criteria for vegetation mapping.

This digital map database, compiled from previously published and unpublished data, and new mapping by the authors, represents the general distribution of bedrock and surficial deposits in the mapped area. Together with the accompanying text file (scvmf.ps, scvmf.pdf, scvmf.txt), it provides current information on the geologic structure and stratigraphy of the area covered. The database delineates map units that are identified by general age and lithology following the stratigraphic nomenclature of the U.S. Geological Survey. The scale of the source maps limits the spatial resolution (scale) of the database to 1:24,000 or smaller.

This part of DS 781 presents data for the faults for the geologic and geomorphic map of the Offshore of Monterey map area, California. The vector data file is included in "Faults_OffshoreMonterey.zip," which is accessible from http://dx.doi.org/10.3133/ofr20161110. The shelf north and east of the Monterey Bay Peninsula in the Offshore of Monterey map area is cut by a diffuse zone of northwest striking, steeply dipping to vertical faults comprising the Monterey Bay Fault Zone (MBFZ). This zone, originally mapped by Greene (1977, 1990), extends about 45 km across Monterey Bay (Map E on sheet 9). Fault strands within the MBFZ are mapped with high-resolution seismic-reflection profiles (sheet 8). Seismic-reflection profiles traversing this diffuse zone in the map area cross as many as 5 faults over a width of about 4 to 5 km (see, for example, figs. 3 and 5 on sheet 8). The zone lacks a continuous "master fault," along which deformation is concentrated. Fault length ranges up to about 20 km (based on mapping outside this map area), but most strands are only about 2- to 7-km long. Faults in this diffuse zone cut through Neogene bedrock and locally appear to minimally disrupt overlying inferred Quaternary sediments. The presence of warped reflections along some fault strands suggests that fault offsets may be both vertical and strike-slip. Specific offshore faults within the zone that are continuous with mapped onshore faults include the Navy Fault, Chupines Fault, and Ord Terrace Fault (Clark and others, 1997; Wagner and others, 2002). Carmel Canyon, a relatively straight northwest-trending arm of the Monterey Canyon system, extends through the southwestern part of the Offshore of Monterey map area. Carmel Canyon has three heads (Greene and others, 2002), two of which extend east and northeast into Carmel Bay within the map area; the third head extends southeast along the main canyon trend for about 3 km beyond the confluence with the heads in Carmel Bay. Carmel Canyon is aligned with and structurally controlled by the San Gregorio fault zone (Greene and others, 1991), an important structure in the distributed transform boundary between the North American and Pacific plates (see, for example, Dickinson and others, 2005). This Fault Zone is part of a regional fault system that is present predominantly in the offshore for about 400 km, from Point Conception in the south (where it is known as the Hosgri Fault; Johnson and Watt, 2012) to Bolinas and Point Reyes in the north (Bruns and others, 2002; Ryan and others, 2008). The San Gregorio Fault Zone in the map area is part of a 90-km-long offshore segment that extends northward from Point Sur (about 24 km south of the map area), across outer Monterey Bay to Point Año Nuevo (51 km north of the map area) (see sheet 9; see also, Weber and Lajoie, 1980; Brabb and others, 1998; Wagner and others, 2002). High-resolution seismic-reflection data collected across the canyon do not clearly image the San Gregorio Fault Zone, due largely to significant depth and steep canyon walls. Accordingly, we have mapped the 1,000- 1,300-m-wide fault zone largely on the presence of prominent, lengthy, geomorphic lineaments (sheets 1 and 2) and both geomorphic and lithologic contrasts across the fault. 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 Bruns, T.R., Cooper, A.K., Carlson, P.R., and McCulloch, D.S., 2002, Structure of the submerged San Andreas and San Gregorio Fault zones in the Gulf of Farallones as inferred from high-resolution seismic-reflection data, in Parsons, T., ed., Crustal structure of the coastal and marine San Francisco Bay region, California: U.S. Geological Survey Professional Paper 1658, p. 77–117, available at http://pubs.usgs.gov/pp/1658/. Brabb, E.E., 1997, Geologic Map of Santa Cruz County, California: A digital database, US Geological Survey Open-File Report 97–489, 1:62,500. Clark, J.C., Dupre, W.R., and Rosenberg, L.L., 1997, Geologic map of the Monterey and Seaside 7.5–minute quadrangles, Monterey County, California–A digital database: U.S. Geological Survey Open-File Report 97-30, 2 sheets, scale 1:24,000, http://pubs.usgs.gov/of/1997/of97-030/ 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 San Gregorio-Hosgri fault zone, coastal California: Geologic evidence and tectonic implications: Geological Society of America Special Paper 391, 43 p. Greene, H.G., Maher, N.M., and Paull, C.K., 2002, Physiography of the Monterey Bay National Marine Sanctuary and implications about continental margin development: Marine Geology, v. 181, p. 55–82. Greene, H.G., Clarke, S.H. and Kennedy, M.P., 1991. Tectonic Evolution of Submarine Canyons Along the California Continental Margin. From Shoreline to Abyss, in Osborne, R.H., ed., Society for Sedimentary Geology, Special Publication No. 46, p. 231–248. Greene, H.G., 1990, Regional tectonics and structural evolution of the Monterey Bay region, central California, in Garrison, R.E., Greene, H.G., Hicks, K.R., Weber, G.E., and Wright, T.L., eds., Geology and tectonics of the central California coastal region, San Francisco to Monterey: American Association of Petroleum Geologists, Pacific Section, Guidebook GB67, p. 31–56. Greene, H.G., 1977, Geology of the Monterey Bay region: U.S. Geological Survey Open-File Report 77–718, 347 p. Greene, H.G., 1990, Regional tectonics and structural evolution of the Monterey Bay region, central California, in Garrison, R.E., Greene, H.G., Hicks, K.R., Weber, G.E., and Wright, T.L., eds., Geology and tectonics of the central California coastal region, San Francisco to Monterey, Pacific Section American Association of Petroleum Geologists, Guidebook GB-67, p. 31–56. Johnson, S.Y., and Watt, J.T., 2012, Influence of fault trend, bends, and convergence on shallow structure and geomorphology of the Hosgri strike-slip fault, offshore Central California: Geosphere, v. 8, p. 1,632–1,656, doi:10.1130/GES00830.1. Ryan, H.F., Parsons, T., and Sliter, R.W., 2008. Vertical tectonic deformation associated with the San Andreas fault zone offshore of San Francisco, California: Tectonophysics, v. 429, p. 209–224, doi:10.1016/j.tecto.2008.06.011. Wagner, D.L., Greene, H.G., Saucedo, G.J., and Pridmore, C.L., 2002, Geologic Map of the Monterey 30' x 60' quadrangle and adjacent areas, California: California Geological Survey Regional Geologic Map Series, scale 1:100,000. Weber, G.E., and Lajoie, K.R., 1980, Map of Quaternary faulting along the San Gregorio fault zone, San Mateo and Santa Cruz Counties, California: U.S. Geological Survey Open-File Report 80–907, 3 sheets, scale 1:24,000, available at http://pubs.er.usgs.gov/publication/ofr80907.

This part of DS 781 presents data for the faults for the geologic and geomorphic map of Monterey Canyon and Vicinity, California. The vector data file is included in "Faults_MontereyCanyon.zip," which is accessible from http://dx.doi.org/10.5066/F7XD0ZQ4. The shelf in the Monterey Bay and Vicinity map area is cut by a diffuse zone of northwest-striking, steeply dipping to vertical faults mapped with high-resolution, seismic-reflection profiles (sheet 8). Faults are mapped on the basis of abrupt truncation or warping of reflections and (or) juxtaposition of reflection panels with different seismic parameters. Seismic profiles traversing this diffuse zone cross as many as 13 faults over a distance of 8 km (for example, fig. 3, sheet 8). Mapped fault lengths in this diffuse zone are typically 2 to 7 km, and the strike of these offshore faults rotates from about 325° to 350° from southwest to northeast. Faults in this diffuse zone cut through Neogene bedrock and locally appear to disrupt overlying latest Quaternary sediments, and the presence of warped reflections along some fault strands suggests there may be both vertical and strike-slip offsets. This broad, distributed zone of deformation resembles the northwest-trending Monterey Bay Fault Zone (Greene, 1977, 1990), which occurs about 10 km farther west in outer Monterey Bay and similarly lacks a lengthy (> 20 km), continuous "master fault." Deformation in both the Monterey Bay Fault Zone and the diffuse zone of faults in the Monterey Bay and Vicinity map area is attributable to its location in the 40-km-wide, northward-narrowing structural zone between two major, right-lateral, strike-slip faults, the San Andreas Fault to the east and the offshore San Gregorio Fault to the west (fig. 1-1) (McCulloch, 1987; Brabb, 1997; Wagner and others, 2002; Dickinson and others, 2005). 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 Brabb, E.E., 1997, Geologic Map of Santa Cruz County, California: A digital database, US Geological Survey Open-File Report 97–489, 1:62,500. 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 San Gregorio-Hosgri Fault Zone, coastal California: Geologic evidence and tectonic implications: Geological Society of America Special Paper 391, 43 p. Greene, H.G., 1977, Geology of the Monterey Bay region: U.S. Geological Survey Open-File Report 77–718, 347 p. Greene, H.G., 1990, Regional tectonics and structural evolution of the Monterey Bay region, central California, in Garrison, R.E., Greene, H.G., Hicks, K.R., Weber, G.E., and Wright, T.L., eds., Geology and tectonics of the central California coastal region, San Francisco to Monterey, Pacific Section American Association of Petroleum Geologists, Guidebook GB-67, p. 31–56. McCulloch, D.S., 1987, Regional geology and hydrocarbon potential of offshore central California, in Scholl, D.W., Grantz, A., and Vedder, J.G., eds., Geology and Resource Potential of the Continental Margin of Western North America and Adjacent Oceans -- Beaufort Sea to Baja California: Houston, Texas, Circum-Pacific Council for Energy and Mineral Resources, Earth Science Series, v. 6., p. 353–401. Wagner, D.L., Greene, H.G., Saucedo, G.J., and Pridmore, C.L., 2002, Geologic Map of the Monterey 30' x 60' quadrangle and adjacent areas, California: California Geological Survey Regional Geologic Map Series, scale 1:100,000.

description: This part of DS 781 presents data for the folds for the geologic and geomorphic map of Monterey Canyon and Vicinity, California. The vector data file is included in "Folds_MontereyCanyon.zip," which is accessible from http://dx.doi.org/10.5066/F7XD0ZQ4. The shelf in the Monterey Bay and Vicinity map area is cut by a diffuse zone of northwest-striking, steeply dipping to vertical faults mapped with high-resolution, seismic-reflection profiles (sheet 8). Faults are mapped on the basis of abrupt truncation or warping of reflections and (or) juxtaposition of reflection panels with different seismic parameters. Seismic profiles traversing this diffuse zone cross as many as 13 faults over a distance of 8 km (for example, fig. 3, sheet 8). Mapped fault lengths in this diffuse zone are typically 2 to 7 km, and the strike of these offshore faults rotates from about 325 to 350 from southwest to northeast. Faults in this diffuse zone cut through Neogene bedrock and locally appear to disrupt overlying latest Quaternary sediments, and the presence of warped reflections along some fault strands suggests there may be both vertical and strike-slip offsets. This broad, distributed zone of deformation resembles the northwest-trending Monterey Bay Fault Zone (Greene, 1977, 1990), which occurs about 10 km farther west in outer Monterey Bay and similarly lacks a lengthy (> 20 km), continuous "master fault." Deformation in both the Monterey Bay Fault Zone and the diffuse zone of faults in the Monterey Bay and Vicinity map area is attributable to its location in the 40-km-wide, northward-narrowing structural zone between two major, right-lateral, strike-slip faults, the San Andreas Fault to the east and the offshore San Gregorio Fault to the west (fig. 1-1) (McCulloch, 1987; Brabb, 1997; Wagner and others, 2002; Dickinson and others, 2005). Folds 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 Brabb, E.E., 1997, Geologic Map of Santa Cruz County, California: A digital database, US Geological Survey Open-File Report 97€“489, 1:62,500. 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 San Gregorio-Hosgri Fault Zone, coastal California: Geologic evidence and tectonic implications: Geological Society of America Special Paper 391, 43 p. Greene, H.G., 1977, Geology of the Monterey Bay region: U.S. Geological Survey Open-File Report 77€“718, 347 p. Greene, H.G., 1990, Regional tectonics and structural evolution of the Monterey Bay region, central California, in Garrison, R.E., Greene, H.G., Hicks, K.R., Weber, G.E., and Wright, T.L., eds., Geology and tectonics of the central California coastal region, San Francisco to Monterey, Pacific Section American Association of Petroleum Geologists, Guidebook GB-67, p. 31€“56. McCulloch, D.S., 1987, Regional geology and hydrocarbon potential of offshore central California, in Scholl, D.W., Grantz, A., and Vedder, J.G., eds., Geology and Resource Potential of the Continental Margin of Western North America and Adjacent Oceans -- Beaufort Sea to Baja California: Houston, Texas, Circum-Pacific Council for Energy and Mineral Resources, Earth Science Series, v. 6., p. 353€“401. Wagner, D.L., Greene, H.G., Saucedo, G.J., and Pridmore, C.L., 2002, Geologic Map of the Monterey 30' x 60' quadrangle and adjacent areas, California: California Geological Survey Regional Geologic Map Series, scale 1:100,000.; abstract: This part of DS 781 presents data for the folds for the geologic and geomorphic map of Monterey Canyon and Vicinity, California. The vector data file is included in "Folds_MontereyCanyon.zip," which is accessible from http://dx.doi.org/10.5066/F7XD0ZQ4. The shelf in the Monterey Bay and Vicinity map area is cut by a diffuse zone of northwest-striking, steeply dipping to vertical faults mapped with high-resolution, seismic-reflection profiles (sheet 8). Faults are mapped on the basis of abrupt truncation or warping of reflections and (or) juxtaposition of reflection panels with different seismic parameters. Seismic profiles traversing this diffuse zone cross as many as 13 faults over a distance of 8 km (for example, fig. 3, sheet 8). Mapped fault lengths in this diffuse zone are typically 2 to 7 km, and the strike of these offshore faults rotates from about 325 to 350 from southwest to northeast. Faults in this diffuse zone cut through Neogene bedrock and locally appear to disrupt overlying latest Quaternary sediments, and the presence of warped reflections along some fault strands suggests there may be both vertical and strike-slip offsets. This broad, distributed zone of deformation resembles the northwest-trending Monterey Bay Fault Zone (Greene, 1977, 1990), which occurs about 10 km farther west in outer Monterey Bay and similarly lacks a lengthy (> 20 km), continuous "master fault." Deformation in both the Monterey Bay Fault Zone and the diffuse zone of faults in the Monterey Bay and Vicinity map area is attributable to its location in the 40-km-wide, northward-narrowing structural zone between two major, right-lateral, strike-slip faults, the San Andreas Fault to the east and the offshore San Gregorio Fault to the west (fig. 1-1) (McCulloch, 1987; Brabb, 1997; Wagner and others, 2002; Dickinson and others, 2005). Folds 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 Brabb, E.E., 1997, Geologic Map of Santa Cruz County, California: A digital database, US Geological Survey Open-File Report 97€“489, 1:62,500. 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 San Gregorio-Hosgri Fault Zone, coastal California: Geologic evidence and tectonic implications: Geological Society of America Special Paper 391, 43 p. Greene, H.G., 1977, Geology of the Monterey Bay region: U.S. Geological Survey Open-File Report 77€“718, 347 p. Greene, H.G., 1990, Regional tectonics and structural evolution of the Monterey Bay region, central California, in Garrison, R.E., Greene, H.G., Hicks, K.R., Weber, G.E., and Wright, T.L., eds., Geology and tectonics of the central California coastal region, San Francisco to Monterey, Pacific Section American Association of Petroleum Geologists, Guidebook GB-67, p. 31€“56. McCulloch, D.S., 1987, Regional geology and hydrocarbon potential of offshore central California, in Scholl, D.W., Grantz, A., and Vedder, J.G., eds., Geology and Resource Potential of the Continental Margin of Western North America and Adjacent Oceans -- Beaufort Sea to Baja California: Houston, Texas, Circum-Pacific Council for Energy and Mineral Resources, Earth Science Series, v. 6., p. 353€“401. Wagner, D.L., Greene, H.G., Saucedo, G.J., and Pridmore, C.L., 2002, Geologic Map of the Monterey 30' x 60' quadrangle and adjacent areas, California: California Geological Survey Regional Geologic Map Series, scale 1:100,000.

This part of DS 781 presents data for faults for the geologic and geomorphic map of the Offshore of Half Moon Bay map area, California. The vector data file is included in "Faults_OffshoreHalfMoonBay.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshoreHalfMoonBay/data_catalog_OffshoreHalfMoonBay.html. The Offshore of Half Moon Bay map area lies about 12 km southwest of the San Andreas Fault, the dominant structure in the distributed, right-lateral, transform boundary between the North American and Pacific plates. The map area straddles the right-lateral San Gregorio Fault, the most important structure west of the San Andreas Fault in this broad zone. The San Gregorio is part of fault system that occurs predominantly in the offshore, extending about 400 km from Point Conception on the south to Bolinas and Point Reyes on the north (Dickinson and others, 2005), intersecting land at a few coastal promontories. In the Offshore of Half Moon Bay map area, the San Gregorio Fault forms a distributed shear zone about 2 to 4.5 km wide that includes two primary diverging fault strands. The eastern strand (also known as the Seal Cove Fault or Coastways Fault) roughly parallels the shoreline, lies onshore for about 3 km at Pillar Point, and locally forms the boundary between outcrops of Cretaceous grantic rocks to the east and Purisima Formation to the west. The western strand (also known as the Frijoles Fault) lies entirely offshore and forms a boundary between the Purisima Formation on the east and undifferentiated Cretaceous and (or) Tertiary rocks (Pigeon Point Formation?) of the Pigeon Point structural block (McCulloch, 1987) on the west. The Pigeon Point block forms a northwest-trending bedrock ridge that extends offshore for about 30 km from Pescadero Point and forms the northwest boundary of the outer Santa Cruz Basin (McCulloch, 1987). Cumulative lateral slip on the San Gregorio Fault zone is thought to range from 4 to 10 mm/yr in this region (U.S. Geological Survey, 2010). Bathymetric (Bathymetry--Offshore Half Moon Bay, California, DS 781) and seismic-reflection data (see field activity S-15-10-NC) reveal that the offshore outcrops of the Purisima Formation between the eastern and western strands of the San Gregorio Fault Zone are spectacularly folded, faulted and rotated by the strike-slip motion and drag along the faults. The entire map area lies along strike with the young, high topography of the Santa Cruz Mountains and Coast Ranges. This regional uplift has been linked to a northwest transpressive bend in the San Andreas Fault (for example, Zoback and others, 1999). Uplift of nearby marine terraces at rates up to 0.44 mm/yr confirms that this uplift includes the coastal zone (Weber and others, 1995). Faults were primarily mapped by interpretation of seismic reflection profile data (see field activity S-15-10-NC). 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 San Gregorio-Hosgri fault zone, coastal California: Geologic evidence and tectonic implications: Geological Society of America Special Paper 391, 43 p. McCulloch, D.S., 1987, Regional geology and hydrocarbon potential of offshore Central California, in Scholl, D.W., Grantz, A., and Vedder, J.G., eds., Geology and resource potential of the continental margin of Western North America and adjacent ocean basins - Beaufort Sea to Baja California: Circum-Pacific Council for Energy and Mineral Resources Earth Science Series, v. 6, p. 353-401. U.S. Geological Survey and California Geological Survey, 2010, Quaternary fault and fold database for the United States, accessed April 5, 2012, from USGS website: http://earthquake.usgs.gov/hazards/qfaults/. Weber, G.E., Nolan, J.M., and Zinn, E.N., 1995, Determination of late Pleistocene-Holocene slip rates along the San Gregorio fault zone, San Mateo and Santa Cruz counties, California: Final Technical Report, National Earthquake Hazard Reduction Program, Contract No. 1434-93-G-2336, 70 p., 4 map sheets. Zoback, M.L., Jachens, R.C., and Olson, J.A., 1999, Abrupt along-strike change in tectonic style: San Andreas fault zone, San Francisco Peninsula: Journal of Geophysical Research, v. 104 (B5), p. 10,719-10,742.

This part of DS 781 presents data for folds for the geologic and geomorphic map of the Offshore of Half Moon Bay map area, California. The vector data file is included in "Folds_OffshoreHalfMoonBay.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshoreHalfMoonBay/data_catalog_OffshoreHalfMoonBay.html. The Offshore of Half Moon Bay map area lies about 12 km southwest of the San Andreas Fault, the dominant structure in the distributed, right-lateral, transform boundary between the North American and Pacific plates. The map area straddles the right-lateral San Gregorio Fault, the most important structure west of the San Andreas Fault in this broad zone. The San Gregorio is part of fault system that occurs predominantly in the offshore, extending about 400 km from Point Conception on the south to Bolinas and Point Reyes on the north (Dickinson and others, 2005), intersecting land at a few coastal promontories. In the Offshore of Half Moon Bay map area, the San Gregorio Fault forms a distributed shear zone about 2 to 4.5 km wide that includes two primary diverging fault strands. The eastern strand (also known as the Seal Cove Fault or Coastways Fault) roughly parallels the shoreline, lies onshore for about 3 km at Pillar Point, and locally forms the boundary between outcrops of Cretaceous grantic rocks to the east and Purisima Formation to the west. The western strand (also known as the Frijoles Fault) lies entirely offshore and forms a boundary between the Purisima Formation on the east and undifferentiated Cretaceous and (or) Tertiary rocks (Pigeon Point Formation?) of the Pigeon Point structural block (McCulloch, 1987) on the west. The Pigeon Point block forms a northwest-trending bedrock ridge that extends offshore for about 30 km from Pescadero Point and forms the northwest boundary of the outer Santa Cruz Basin (McCulloch, 1987). Cumulative lateral slip on the San Gregorio Fault zone is thought to range from 4 to 10 mm/yr in this region (U.S. Geological Survey, 2010). Bathymetric (Bathymetry--Offshore Half Moon Bay, California, DS 781) and seismic-reflection data (see field activity S-15-10-NC) reveal that the offshore outcrops of the Purisima Formation between the eastern and western strands of the San Gregorio Fault Zone are spectacularly folded, faulted and rotated by the strike-slip motion and drag along the faults. The entire map area lies along strike with the young, high topography of the Santa Cruz Mountains and Coast Ranges. This regional uplift has been linked to a northwest transpressive bend in the San Andreas Fault (for example, Zoback and others, 1999). Uplift of nearby marine terraces at rates up to 0.44 mm/yr confirms that this uplift includes the coastal zone (Weber and others, 1995). Folds were primarily mapped by interpretation of seismic reflection profile data (see field activity S-15-10-NC). 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 San Gregorio-Hosgri fault zone, coastal California: Geologic evidence and tectonic implications: Geological Society of America Special Paper 391, 43 p. McCulloch, D.S., 1987, Regional geology and hydrocarbon potential of offshore Central California, in Scholl, D.W., Grantz, A., and Vedder, J.G., eds., Geology and resource potential of the continental margin of Western North America and adjacent ocean basins - Beaufort Sea to Baja California: Circum-Pacific Council for Energy and Mineral Resources Earth Science Series, v. 6, p. 353-401. U.S. Geological Survey and California Geological Survey, 2010, Quaternary fault and fold database for the United States, accessed April 5, 2012, from USGS website: http://earthquake.usgs.gov/hazards/qfaults/. Weber, G.E., Nolan, J.M., and Zinn, E.N., 1995, Determination of late Pleistocene-Holocene slip rates along the San Gregorio fault zone, San Mateo and Santa Cruz counties, California: Final Technical Report, National Earthquake Hazard Reduction Program, Contract No. 1434-93-G-2336, 70 p., 4 map sheets. Zoback, M.L., Jachens, R.C., and Olson, J.A., 1999, Abrupt along-strike change in tectonic style: San Andreas fault zone, San Francisco Peninsula: Journal of Geophysical Research, v. 104 (B5), p. 10,719-10,742.

This part of DS 781 presents data for the folds for the geologic and geomorphic map of the Offshore Aptos map area, California. The vector data file is included in "Folds_OffshoreAptos.zip," which is accessible from http://dx.doi.org/10.5066/F7K35RQB. The shelf in the Offshore of Aptos map area is cut by a diffuse zone of northwest-striking, steeply dipping to vertical faults mapped with high-resolution, seismic-reflection profiles (sheet 8). Faults are mapped on the basis of abrupt truncation or warping of reflections and (or) juxtaposition of reflection panels with different seismic parameters. Seismic profiles traversing this diffuse zone cross as many as 13 faults over a distance of 8 km. Mapped fault lengths in this diffuse zone are typically 2 to 7 km, and the strike of these offshore faults rotates from about 325° to 350° from southwest to northeast. Faults in this diffuse zone cut through Neogene bedrock and locally appear to disrupt overlying latest Quaternary sediments, and the presence of warped reflections along some fault strands suggests there may be both vertical and strike-slip offsets. This broad, distributed zone of deformation resembles the northwest-trending Monterey Bay Fault Zone (Greene, 1977, 1990), which occurs about 10 km farther west in outer Monterey Bay and similarly lacks a lengthy (> 20 km), continuous "master fault." Deformation in both the Monterey Bay Fault Zone and the diffuse zone of faults in the Offshore of Aptos map area is attributable to its location in the 40-km-wide, northward-narrowing structural zone between two major, right-lateral, strike-slip faults, the San Andreas Fault to the east and the offshore San Gregorio Fault to the west (McCulloch, 1987; Brabb, 1997; Wagner and others, 2002; Dickinson and others, 2005). Folds 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 Brabb, E.E., 1997, Geologic Map of Santa Cruz County, California: A digital database, US Geological Survey Open-File Report 97-489, 1:62,500. 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 San Gregorio-Hosgri Fault Zone, coastal California: Geologic evidence and tectonic implications: Geological Society of America Special Paper 391, 43 p. Greene, H.G., 1977, Geology of the Monterey Bay region: U.S. Geological Survey Open-File Report 77-718, 347 p. Greene, H.G., 1990, Regional tectonics and structural evolution of the Monterey Bay region, central California, in Garrison, R.E., Greene, H.G., Hicks, K.R., Weber, G.E., and Wright, T.L., eds., Geology and tectonics of the central California coastal region, San Francisco to Monterey, Pacific Section American Association of Petroleum Geologists, Guidebook GB-67, p. 31-56. McCulloch, D.S., 1987, Regional geology and hydrocarbon potential of offshore central California, in Scholl, D.W., Grantz, A., and Vedder, J.G., eds., Geology and Resource Potential of the Continental Margin of Western North America and Adjacent Oceans -- Beaufort Sea to Baja California: Houston, Texas, Circum-Pacific Council for Energy and Mineral Resources, Earth Science Series, v. 6., p. 353-401. Wagner, D.L., Greene, H.G., Saucedo, G.J., and Pridmore, C.L., 2002, Geologic Map of the Monterey 30' x 60' quadrangle and adjacent areas, California: California Geological Survey Regional Geologic Map Series, scale 1:100,000.

This part of DS 781 presents data for the faults for the geologic and geomorphic map of the Offshore Aptos map area, California. The vector data file is included in "Faults_OffshoreAptos.zip," which is accessible from http://dx.doi.org/10.5066/F7K35RQB. The shelf in the Offshore of Aptos map area is cut by a diffuse zone of northwest-striking, steeply dipping to vertical faults mapped with high-resolution, seismic-reflection profiles (sheet 8). Faults are mapped on the basis of abrupt truncation or warping of reflections and (or) juxtaposition of reflection panels with different seismic parameters. Seismic profiles traversing this diffuse zone cross as many as 13 faults over a distance of 8 km. Mapped fault lengths in this diffuse zone are typically 2 to 7 km, and the strike of these offshore faults rotates from about 325° to 350° from southwest to northeast. Faults in this diffuse zone cut through Neogene bedrock and locally appear to disrupt overlying latest Quaternary sediments, and the presence of warped reflections along some fault strands suggests there may be both vertical and strike-slip offsets. This broad, distributed zone of deformation resembles the northwest-trending Monterey Bay Fault Zone (Greene, 1977, 1990), which occurs about 10 km farther west in outer Monterey Bay and similarly lacks a lengthy (> 20 km), continuous "master fault." Deformation in both the Monterey Bay Fault Zone and the diffuse zone of faults in the Offshore of Aptos map area is attributable to its location in the 40-km-wide, northward-narrowing structural zone between two major, right-lateral, strike-slip faults, the San Andreas Fault to the east and the offshore San Gregorio Fault to the west (McCulloch, 1987; Brabb, 1997; Wagner and others, 2002; Dickinson and others, 2005). 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 Brabb, E.E., 1997, Geologic Map of Santa Cruz County, California: A digital database, US Geological Survey Open-File Report 97-489, 1:62,500. 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 San Gregorio-Hosgri Fault Zone, coastal California: Geologic evidence and tectonic implications: Geological Society of America Special Paper 391, 43 p. Greene, H.G., 1977, Geology of the Monterey Bay region: U.S. Geological Survey Open-File Report 77-718, 347 p. Greene, H.G., 1990, Regional tectonics and structural evolution of the Monterey Bay region, central California, in Garrison, R.E., Greene, H.G., Hicks, K.R., Weber, G.E., and Wright, T.L., eds., Geology and tectonics of the central California coastal region, San Francisco to Monterey, Pacific Section American Association of Petroleum Geologists, Guidebook GB-67, p. 31-56. McCulloch, D.S., 1987, Regional geology and hydrocarbon potential of offshore central California, in Scholl, D.W., Grantz, A., and Vedder, J.G., eds., Geology and Resource Potential of the Continental Margin of Western North America and Adjacent Oceans -- Beaufort Sea to Baja California: Houston, Texas, Circum-Pacific Council for Energy and Mineral Resources, Earth Science Series, v. 6., p. 353-401. Wagner, D.L., Greene, H.G., Saucedo, G.J., and Pridmore, C.L., 2002, Geologic Map of the Monterey 30' x 60' quadrangle and adjacent areas, California: California Geological Survey Regional Geologic Map Series, scale 1:100,000.

This part of DS 781 presents data for the folds for the geologic and geomorphic map of the Offshore Monterey map area, California. The vector data file is included in "Folds_OffshoreMonterey.zip," which is accessible from http://dx.doi.org/10.5066/F7F47M6T. The shelf north and east of the Monterey Bay Peninsula in the Offshore of Monterey map area is cut by a diffuse zone of northwest striking, steeply dipping to vertical faults comprising the Monterey Bay Fault Zone (MBFZ). This zone, originally mapped by Greene (1977, 1990), extends about 45 km across Monterey Bay (Map E on sheet 9). Fault strands within the MBFZ are mapped with high-resolution seismic-reflection profiles (sheet 8). Seismic-reflection profiles traversing this diffuse zone in the map area cross as many as 5 faults over a width of about 4 to 5 km (see, for example, figs. 3 and 5 on sheet 8). The zone lacks a continuous "master fault," along which deformation is concentrated. Fault length ranges up to about 20 km (based on mapping outside this map area), but most strands are only about 2- to 7-km long. Faults in this diffuse zone cut through Neogene bedrock and locally appear to minimally disrupt overlying inferred Quaternary sediments. The presence of warped reflections along some fault strands suggests that fault offsets may be both vertical and strike-slip. Specific offshore faults within the zone that are continuous with mapped onshore faults include the Navy Fault, Chupines Fault, and Ord Terrace Fault (Clark and others, 1997; Wagner and others, 2002). Carmel Canyon, a relatively straight northwest-trending arm of the Monterey Canyon system, extends through the southwestern part of the Offshore of Monterey map area. Carmel Canyon has three heads (Greene and others, 2002), two of which extend east and northeast into Carmel Bay within the map area; the third head extends southeast along the main canyon trend for about 3 km beyond the confluence with the heads in Carmel Bay. Carmel Canyon is aligned with and structurally controlled by the San Gregorio fault zone (Greene and others, 1991), an important structure in the distributed transform boundary between the North American and Pacific plates (see, for example, Dickinson and others, 2005). This Fault Zone is part of a regional fault system that is present predominantly in the offshore for about 400 km, from Point Conception in the south (where it is known as the Hosgri Fault; Johnson and Watt, 2012) to Bolinas and Point Reyes in the north (Bruns and others, 2002; Ryan and others, 2008). The San Gregorio Fault Zone in the map area is part of a 90-km-long offshore segment that extends northward from Point Sur (about 24 km south of the map area), across outer Monterey Bay to Point Año Nuevo (51 km north of the map area) (see sheet 9; see also, Weber and Lajoie, 1980; Brabb and others, 1998; Wagner and others, 2002). High-resolution seismic-reflection data collected across the canyon do not clearly image the San Gregorio Fault Zone, due largely to significant depth and steep canyon walls. Accordingly, we have mapped the 1,000- 1,300-m-wide fault zone largely on the presence of prominent, lengthy, geomorphic lineaments (sheets 1 and 2) and both geomorphic and lithologic contrasts across the fault. Folds 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 Bruns, T.R., Cooper, A.K., Carlson, P.R., and McCulloch, D.S., 2002, Structure of the submerged San Andreas and San Gregorio Fault zones in the Gulf of Farallones as inferred from high-resolution seismic-reflection data, in Parsons, T., ed., Crustal structure of the coastal and marine San Francisco Bay region, California: U.S. Geological Survey Professional Paper 1658, p. 77–117, available at http://pubs.usgs.gov/pp/1658/. Brabb, E.E., 1997, Geologic Map of Santa Cruz County, California: A digital database, US Geological Survey Open-File Report 97–489, 1:62,500. Clark, J.C., Dupre, W.R., and Rosenberg, L.L., 1997, Geologic map of the Monterey and Seaside 7.5–minute quadrangles, Monterey County, California–A digital database: U.S. Geological Survey Open-File Report 97-30, 2 sheets, scale 1:24,000, http://pubs.usgs.gov/of/1997/of97-030/ 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 San Gregorio-Hosgri fault zone, coastal California: Geologic evidence and tectonic implications: Geological Society of America Special Paper 391, 43 p. Greene, H.G., Maher, N.M., and Paull, C.K., 2002, Physiography of the Monterey Bay National Marine Sanctuary and implications about continental margin development: Marine Geology, v. 181, p. 55–82. Greene, H.G., Clarke, S.H. and Kennedy, M... Visit https://dataone.org/datasets/56b70959-2946-472d-b924-f1bb8bd88dc2 for complete metadata about this dataset.

This part of DS 781 presents data for the geologic and geomorphic map of the Offshore Aptos map area, California. The vector data file is included in "Geology_OffshoreAptos.zip," which is accessible from http://dx.doi.org/10.5066/F7K35RQB. Most of the offshore occupies very gently dipping (about 0.1° to 0.4°) continental shelf, extending from the nearshore to water depths of about 70 m. In the southwestern part of the map, the shelf is incised by the north-trending head of Soquel Canyon, which has a maximum depth of 260 m on the south edge of the map. The shelf is underlain by late Neogene bedrock and a variably thick (as much as 32 m) late Quaternary sediment cover. Sea level has risen 120 to 130 m over about the last 21,000 years (for example, Stanford and others, 2011), leading to broadening of the continental shelf, progressive eastward migration of the shoreline and wave-cut platform, and transgressive erosion and deposition. Sea-level rise was apparently not steady during this period, leading to development of shoreline angles and adjacent submerged wave-cut platforms and risers (Kern, 1977). These features commonly are commonly removed by erosion or buried by shelf sediment, however their original morphology is at least partly preserved along the rim of upper Soquel Canyon. Geologic map units include three wave-cut platforms (units Qwp1, Qwp2, Qwp3) and risers (units Qwpr1, Qwpr2, Qwpr3), separated by shoreline angles at depths of approximately 96 to 100 m, 108 m, and 120 to 125 m. The deepest paleoshoreline (about 120 m deep) approximately corresponds to sea level during the final stages of the last sea-level lowstand (Stanford and others, 2011). Submergence during sea-level rise also cut off the direct connection between Soquel Canyon and coastal watersheds, rendering the submarine canyon relatively inactive. Although slightly sheltered in Monterey Bay, the Offshore of Aptos map area is now subjected to significant wave energy and strong currents. Shelf morphology and geology are also affected by local faulting, folding, and uplift. The shelf in the Offshore of Aptos map area is cut by a diffuse zone of northwest-striking, steeply dipping to vertical faults mapped with high-resolution, seismic-reflection profiles. Faults are mapped on the basis of abrupt truncation or warping of reflections and (or) juxtaposition of reflection panels with different seismic parameters. Seismic profiles traversing this diffuse zone cross as many as 13 faults over a distance of 8 km. Mapped fault lengths in this diffuse zone are typically 2 to 7 km, and the strike of these offshore faults rotates from about 325° to 350° from southwest to northeast. Faults in this diffuse zone cut through Neogene bedrock and locally appear to disrupt overlying latest Quaternary sediments, and the presence of warped reflections along some fault strands suggests there may be both vertical and strike-slip offsets. This broad, distributed zone of deformation resembles the northwest-trending Monterey Bay Fault Zone (Greene, 1977, 1990), which occurs about 10 km farther west in outer Monterey Bay and similarly lacks a lengthy continuous "master fault." Deformation in both the Monterey Bay Fault zone and the diffuse zone of faults in the Offshore of Aptos map area is attributable to its location in the 40-km-wide, northward-narrowing structural zone between two major, right-lateral, strike-slip faults, the San Andreas Fault to the east and the offshore San Gregorio Fault to the west (McCulloch, 1987; Brabb, 1997; Wagner and others, 2002; Dickinson and others, 2005). Emergent late Pleistocene marine terraces on the south flank of the Santa Cruz Mountains in and north of northeastern Monterey Bay are as high as 125 m. Anderson and Menking (1994) report a 50- to 60-m elevation for the shoreline angle tied to the lowest emergent terrace (assigned to oxygen isotope stage 5c or 5e) in the Aptos vicinity, suggesting an uplift rate of about 0.4 to 0.6 mm/yr. Anderson (1990) and Anderson and Menking (1994) attributed this uplift to advection of crust around a bend in the San Andreas Fault, which lies 13 km northeast of the Aptos shoreline. The uplifted region in this tectonic model would include the nearshore and shelf of northeastern Monterey Bay, but there are considerable shore-normal uplift gradients and offshore uplift rates are not constrained. From La Selva Beach west to the western edge of the map area, the upper Miocene and Pliocene Purisima Formation (unit Tp; Powell and others, 2007) forms discontinuous outcrops that extend from coastal bluffs into the offshore to depths as great as 25 m. The seafloor outcrops are most prominent offshore of Soquel Point and have relatively low relief, probably in large part due to low structural dips. The Purisima Formation also forms outcrops in the steep walls of the head of Soquel Canyo... Visit https://dataone.org/datasets/07e9273a-5929-4b73-ad70-e63c3f1fc989 for complete metadata about this dataset.

This part of DS 781 presents the seafloor-character map Offshore of Aptos, California. The raster data file is included in "SeafloorCharacter_2m_OffshoreAptos.zip," which is accessible from http://dx.doi.org/10.5066/F7K35RQB. This raster-format seafloor character map shows five substrate classes Offshore of Aptos, California. The substrate classes mapped in this area have been further divided into the following California Marine Life Protection Act depth zones and slope classes: Depth Zone 2 (intertidal to 30 m), Depth Zone 3 (30 to 100 m), Depth Zone 4 (100 to 200 m), Slope Class 1 (0 degrees - 5 degrees), and Slope Class 2 (5 degrees - 30 degrees). Depth Zone 1 (intertidal), Depth Zone 5 (greater than 200 m), and Slopes Classes 3-4 (greater than 30 degrees) are not present in the region covered by this block. The map is created using a supervised classification method described by Cochrane (2008). References Cited: California Department of Fish and Game, 2008, California Marine Life Protection Act master plan for marine protected areas; Revised draft: California Department of Fish and Game, accessed April 5 2011, at http://www.dfg.ca.gov/mlpa/masterplan.asp. Cochrane, G.R., 2008, Video-supervised classification of sonar data for mapping seafloor habitat, in Reynolds, J.R., and Greene, H.G., eds., Marine habitat mapping technology for Alaska: Fairbanks, University of Alaska, Alaska Sea Grant College Program, p. 185-194, accessed April 5, 2011, at http://doc.nprb.org/web/research/research%20pubs/615_habitat_mapping_workshop/Individual%20Chapters%20High-Res/Ch13%20Cochrane.pdf. Sappington, J.M., Longshore, K.M., and Thompson, D.B., 2007, Quantifying landscape ruggedness for animal habitat analysis--A case study using bighorn sheep in the Mojave Desert: Journal of Wildlife Management, v. 71, p. 1419-1426.

This part of DS 781 presents data for the geologic and geomorphic map of the Offshore of Point Reyes map area, California. The vector data file is included in "Faults_OffshorePointReyes.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshorePointReyes/data_catalog_OffshorePointReyes.html.

Faults in the Point Reyes map area are identified on seismic-reflection data based on abrupt truncation or warping of reflections and (or) juxtaposition of reflection panels with different seismic parameters such as reflection presence, amplitude, frequency, geometry, continuity, and vertical sequence. The Point Reyes Fault Zone runs through the map area and is an offshore curvilinear reverse fault zone with predominantly north-side-up motion (Hoskins and Griffiths, 1971; McCulloch, 1987; Heck and others, 1990; Stozek, 2012) that likely connects with the western San Gregorio fault further to the south (Ryan and others, 2008), making it part of the San Andreas Fault System. The Point Reyes Fault Zone is characterized by a 5 to 11 km-wide zone of deformation in the shallow subsurface that is associated with two main fault structures, the Point Reyes Fault and the western Point Reyes Fault. Near the Point Reyes headland, vertical displacement of granitic basement across the Point Reyes Fault is at least 1.4 km (McCulloch, 1987). Offshore Double Point, vertical displacement on the Point Reyes Fault is difficult to assess because subsurface age constraints from nearby wells are lacking, and there are few offset horizons across the fault imaged on available seismic data. However, warping and folding of Neogene strata are clearly visible on high-resolution seismic data . The western Point Reyes Fault is defined by a broad anticlinal structure visible in both industry and high-resolution seismic datasets that exhibits that same sense of vergence (north-side-up) as the Point Reyes Fault.

Faults were primarily mapped by interpretation of seismic reflection profile data (see field activity S-8-09-NC). The seismic reflection profiles were collected in 2009.

References Cited

Heck, R.G., Edwards, E.B., Kronen, J.D., Jr., and Willingham, C.R., 1990, Petroleum potential of the offshore outer Santa Cruz and Bodega basins, California, in Garrison, R.E., Greene, H.G., Hicks, K.R., Weber, G.E., and Wright, T.L., eds. Geology and tectonics of the central California coastal region, San Francisco to Monterey: Pacific Section, American Association of Petroleum Geologists Bulletin GB67, p. 143-164.

Hoskins E.G., Griffiths, J.R., 1971, Hydrocarbon potential of northern and central California offshore: American Association of Petroleum Geologists Memoir 15, p. 212-228.

McCulloch, D.S., 1987, Regional geology and hydrocarbon potential of offshore central California, in Scholl, D.W., Grantz, A., and Vedder, J.G., eds., Geology and Resource Potential of the Continental Margin of Western North America and Adjacent Oceans Beaufort Sea to Baja California: Houston, Texas, Circum-Pacific Council for Energy and Mineral Resources, Earth Science Series, v. 6., p. 353-401.

Ryan, H.F., Parsons, T., and Sliter, R.W., 2008, Vertical tectonic deformation associated with the San Andreas Fault offshore of San Francisco, California: Tectonophysics, v. 475, p. 209-223.

Stozek, B.A., 2012, Geophysical evidence for Quaternary deformation within the offshore San Andreas fault system, northern California: Masters Thesis, San Francisco State University, 141 p.

This part of DS 781 presents data for the geologic and geomorphic map of the Offshore of Point Reyes map area, California. The vector data file is included in "Folds_OffshorePointReyes.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshorePointReyes/data_catalog_OffshorePointReyes.html.

Folds in the Point Reyes map area are identified on seismic-reflection data based on abrupt truncation or warping of reflections and (or) juxtaposition of reflection panels with different seismic parameters such as reflection presence, amplitude, frequency, geometry, continuity, and vertical sequence. The Point Reyes Fault Zone runs through the map area and is an offshore curvilinear reverse fault zone with predominantly north-side-up motion (Hoskins and Griffiths, 1971; McCulloch, 1987; Heck and others, 1990; Stozek, 2012) that likely connects with the western San Gregorio fault further to the south (Ryan and others, 2008), making it part of the San Andreas Fault System. The Point Reyes Fault Zone is characterized by a 5 to 11 km-wide zone of deformation in the shallow subsurface that is associated with two main fault structures, the Point Reyes Fault and the western Point Reyes Fault. Near the Point Reyes headland, vertical displacement of granitic basement across the Point Reyes Fault is at least 1.4 km (McCulloch, 1987). Offshore Double Point, vertical displacement on the Point Reyes Fault is difficult to assess because subsurface age constraints from nearby wells are lacking, and there are few offset horizons across the fault imaged on available seismic data. However, warping and folding of Neogene strata are clearly visible on high-resolution seismic data. The western Point Reyes Fault is defined by a broad anticlinal structure visible in both industry and high-resolution seismic datasets that exhibits that same sense of vergence (north-side-up) as the Point Reyes Fault.

Folds were primarily mapped by interpretation of seismic reflection profile data (see field activity S-8-09-NC). The seismic reflection profiles were collected in 2009.

References Cited

Heck, R.G., Edwards, E.B., Kronen, J.D., Jr., and Willingham, C.R., 1990, Petroleum potential of the offshore outer Santa Cruz and Bodega basins, California, in Garrison, R.E., Greene, H.G., Hicks, K.R., Weber, G.E., and Wright, T.L., eds. Geology and tectonics of the central California coastal region, San Francisco to Monterey: Pacific Section, American Association of Petroleum Geologists Bulletin GB67, p. 143-164.

Hoskins E.G., Griffiths, J.R., 1971, Hydrocarbon potential of northern and central California offshore: American Association of Petroleum Geologists Memoir 15, p. 212-228.

McCulloch, D.S., 1987, Regional geology and hydrocarbon potential of offshore central California, in Scholl, D.W., Grantz, A., and Vedder, J.G., eds., Geology and Resource Potential of the Continental Margin of Western North America and Adjacent Oceans Beaufort Sea to Baja California: Houston, Texas, Circum-Pacific Council for Energy and Mineral Resources, Earth Science Series, v. 6., p. 353-401.

Ryan, H.F., Parsons, T., and Sliter, R.W., 2008, Vertical tectonic deformation associated with the San Andreas Fault offshore of San Francisco, California: Tectonophysics, v. 475, p. 209-223.

Stozek, B.A., 2012, Geophysical evidence for Quaternary deformation within the offshore San Andreas fault system, northern California: Masters Thesis, San Francisco State University, 141 p.

This part of DS 781 presents data of faults for the geologic and geomorphologic map of the Drakes Bay and Vicinity map area, California. The vector data file is included in "Faults_DrakesBay.zip," which is accessible from http://pubs.usgs.gov/ds/781/DrakesBay/data_catalog_DrakesBay.html.

Faults in the Drakes Bay and Vicinity map area are identified on seismic-reflection data based on abrupt truncation or warping of reflections and (or) juxtaposition of reflection panels with different seismic parameters such as reflection presence, amplitude, frequency, geometry, continuity, and vertical sequence. The Point Reyes Fault Zone runs through the map area and is an offshore curvilinear reverse fault zone with predominantly north-side-up motion (Hoskins and Griffiths, 1971; McCulloch, 1987; Heck and others, 1990; Stozek, 2012) that likely connects with the western San Gregorio fault further to the south (Ryan and others, 2008), making it part of the San Andreas Fault System. The Point Reyes Fault Zone is characterized by a 5 to 11 km-wide zone of deformation in the shallow subsurface that is associated with two main fault structures, the Point Reyes Fault and the western Point Reyes Fault. Near the Point Reyes headland, vertical displacement of granitic basement across the Point Reyes Fault is at least 1.4 km (McCulloch, 1987). Offshore Double Point, vertical displacement on the Point Reyes Fault is difficult to assess because subsurface age constraints from nearby wells are lacking, and there are few offset horizons across the fault imaged on available seismic data. However, warping and folding of Neogene strata are clearly visible on high-resolution seismic data (see field activity S-8-09-NC). The western Point Reyes Fault is defined by a broad anticlinal structure visible in both industry and high-resolution seismic datasets that exhibits that same sense of vergence (north-side-up) as the Point Reyes Fault.

Faults were primarily mapped by interpretation of seismic reflection profile data (see field activity S-8-09-NC). The seismic reflection profiles were collected between 2006 and 2009.

References Cited

Heck, R.G., Edwards, E.B., Kronen, J.D., Jr., and Willingham, C.R., 1990, Petroleum potential of the offshore outer Santa Cruz and Bodega basins, California, in Garrison, R.E., Greene, H.G., Hicks, K.R., Weber, G.E., and Wright, T.L., eds. Geology and tectonics of the central California coastal region, San Francisco to Monterey: Pacific Section, American Association of Petroleum Geologists Bulletin GB67, p. 143-164.

Hoskins E.G., Griffiths, J.R., 1971, Hydrocarbon potential of northern and central California offshore: American Association of Petroleum Geologists Memoir 15, p. 212-228.

McCulloch, D.S., 1987, Regional geology and hydrocarbon potential of offshore central California, in Scholl, D.W., Grantz, A., and Vedder, J.G., eds., Geology and Resource Potential of the Continental Margin of Western North America and Adjacent Oceans-Beaufort Sea to Baja California: Houston, Texas, Circum-Pacific Council for Energy and Mineral Resources, Earth Science Series, v. 6., p. 353-401.

Ryan, H.F., Parsons, T., and Sliter, R.W., 2008, Vertical tectonic deformation associated with the San Andreas Fault offshore of San Francisco, California: Tectonophysics, v. 475, p. 209-223.

Stozek, B.A., 2012, Geophysical evidence for Quaternary deformation within the offshore San Andreas fault system, northern California: Masters Thesis, San Francisco State University, 141 p.

This part of DS 781 presents data of folds for the geologic and geomorphologic map of the Drakes Bay and Vicinity map area, California. The vector data file is included in "Folds_DrakesBay.zip," which is accessible from http://pubs.usgs.gov/ds/781/DrakesBay/data_catalog_DrakesBay.html.

Folds in the Drakes Bay and Vicinity map area are identified on seismic-reflection data based on abrupt truncation or warping of reflections and (or) juxtaposition of reflection panels with different seismic parameters such as reflection presence, amplitude, frequency, geometry, continuity, and vertical sequence. The Point Reyes Fault Zone runs through the map area and is an offshore curvilinear reverse fault zone with predominantly north-side-up motion (Hoskins and Griffiths, 1971; McCulloch, 1987; Heck and others, 1990; Stozek, 2012) that likely connects with the western San Gregorio fault further to the south (Ryan and others, 2008), making it part of the San Andreas Fault System. The Point Reyes Fault Zone is characterized by a 5 to 11 km-wide zone of deformation in the shallow subsurface that is associated with two main fault structures, the Point Reyes Fault and the western Point Reyes Fault. Near the Point Reyes headland, vertical displacement of granitic basement across the Point Reyes Fault is at least 1.4 km (McCulloch, 1987). Offshore Double Point, vertical displacement on the Point Reyes Fault is difficult to assess because subsurface age constraints from nearby wells are lacking, and there are few offset horizons across the fault imaged on available seismic data. However, warping and folding of Neogene strata are clearly visible on high-resolution seismic data (see field activity S-8-09-NC). The western Point Reyes Fault is defined by a broad anticlinal structure visible in both industry and high-resolution seismic datasets that exhibits that same sense of vergence (north-side-up) as the Point Reyes Fault.

Folds were primarily mapped by interpretation of seismic reflection profile data (see field activity S-8-09-NC). The seismic reflection profiles were collected between 2006 in 2009.

References Cited

Heck, R.G., Edwards, E.B., Kronen, J.D., Jr., and Willingham, C.R., 1990, Petroleum potential of the offshore outer Santa Cruz and Bodega basins, California, in Garrison, R.E., Greene, H.G., Hicks, K.R., Weber, G.E., and Wright, T.L., eds. Geology and tectonics of the central California coastal region, San Francisco to Monterey: Pacific Section, American Association of Petroleum Geologists Bulletin GB67, p. 143-164.

Hoskins E.G., Griffiths, J.R., 1971, Hydrocarbon potential of northern and central California offshore: American Association of Petroleum Geologists Memoir 15, p. 212-228.

McCulloch, D.S., 1987, Regional geology and hydrocarbon potential of offshore central California, in Scholl, D.W., Grantz, A., and Vedder, J.G., eds., Geology and Resource Potential of the Continental Margin of Western North America and Adjacent Oceans-Beaufort Sea to Baja California: Houston, Texas, Circum-Pacific Council for Energy and Mineral Resources, Earth Science Series, v. 6., p. 353-401.

Ryan, H.F., Parsons, T., and Sliter, R.W., 2008, Vertical tectonic deformation associated with the San Andreas Fault offshore of San Francisco, California: Tectonophysics, v. 475, p. 209-223.

Stozek, B.A., 2012, Geophysical evidence for Quaternary deformation within the offshore San Andreas fault system, northern California: Masters Thesis, San Francisco State University, 141 p.