Search for geospatial/GIS data

Find GIS data held at MIT and other institutions

128 results returned

  1. Title: Primary Care Health Professional Shortage Areas, California, 2015

    Contributors:

    Summary: This polygon shapefile contains primary health care professional shortage areas (HPSAs) in California. On January 26, 2004, the California Healthcare Workforce Policy Commission (Commission) formally adopted a means to create the PCSA map. The process for identifying PCSAs uses the rule base listed below. In March, 2015, the OSHPD staff presented the Commission with information suggesting an update to the map to include current data on (1) physicians, (2) poverty and (3) population. Percent below Poverty Level (100%) Value Range Weighted Score 5.0 or Less 0 5.1 - 10.0 1 10.1 - 15.0 2 15.1 - 20.0 3 20.1 - 25.0 4 25.1 or Greater 5 (maximum) Physician-to-Population Ratio Value Range Weighted Score Lower than 1:1,000 0 1:1,000 to 1:1,500 1 1:1,500 to 1:2,000 2 1:2,000 to 1:2,500 3 1:2,500 to 1:3,000 4 Higher than 1:3,000 5 (maximum) * Any MSSA with a score of 5 or greater is defined as a PCSA. PCSAs are used as a means to help the Commission rank applications based on the number of program graduates and training sites inside areas of unmet need. PCSAs are the only consistently applied rule base to defining shortages of physicians, as the other designations are applicant based and require prior knowledge that a shortage might exist. This data is aggregated by Medical Service Study Area (MSSA) to obtain a count of primary care physicians by MSSA. Primary Care Shortage Areas are updated Annually and are used in the Song-Brown Grant Program for Family Medicine, Family Nurse Practitioner-Physician Assistant and Primary Care Residency programs. This update to data for the PCSA was approved by the California Healthcare Workforce Policy Commission on March 4, 2015. This layer is part of the Healthcare Atlas of California. This data for Primary Care Shortage Area (PCSA) was developed by the Office of Statewide Health Planning and Development's (OSHPD) Healthcare Workforce Development Division (HWDD). The data is used to support the following programatic areas: 1) encourage demographically underrepresented groups to pursue healthcare careers 2) identifies geographic areas of unmet need, and 3) encourages primary care physicians and non-physician practitioners to provide healthcare in medically underserved areas in California. O'Neill, M. and California Office of Statewide Health Planning and Development. (2015). Primary Care Health Professional Shortage Areas, California, 2015. California Office of Statewide Health Planning and Development. Available at: http://purl.stanford.edu/zr629js5551. 1. The recipient will not distribute copies of the data or make the DATA available to a third party. The recipient may transmit to a third party colleague in hard copy or electronically, minimal amounts of the California Healthcare Workforce Catalog (CWHC) data for scholarly, educational, or scientific research or professional use bit in no case for re-sale. In addition, the recipient has the right to use, with appropriate credit, maps, figures, tables and excerpts derived from the CHWC in the recipients own scientific, scholarly and educational works. 2. The recipient will not resell the data or portions of the data 3. Maps, figures, tables and data from the CHWC should be appropriately attributed trough the use of the following citation: California Healthcare Workforce Catalog (CWHC). April 2005. California Health and Human Services Agency, Office of Statewide Health Planning and Development, Healthcare Workforce and Development Division, Sacramento CA. 4. Whenever, HWDD has knowledge or reason to believe that the recipient has failed to observe the terms and conditions of this agreement, HWDD will notify the recipient of the concerns. The recipient is required to provide adequate documentation or information to establish HWDD's satisfaction that the concerns are without merit, or to remedy the situation within 30 days or within a reasonable timeframe agreed to by both parties. Use Constraints: The State of California, the California Health and Human Services Agency and the Office of Statewide Health Planning and Development make no representations or warranties regarding the accuracy of data or maps. The user will not seek to hold the State, the Agency or the Office liable under any circumstances for any damages with respect to any claim by the user or any third party on account of or arising from the use of data or maps. The user will cite the California Health and Human Services Agency and/or the Office as the original source of the data, but will clearly denote cases where the original data have been updated, modified, or in any way altered from the original condition. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.

    View full record

  2. Title: Census Zip Code Tabulation Areas, California, 2010

    Contributors:

    Summary: This polygon shapefile represents zip code tabulation areas (ZCTAs) for the state of California. These data were gathered from the 2010 Census demographics update and contain keys for ZCTAs, centroid coordinates, demographic fields for age, gender, race and ethnicity, and housing information including living quarters, institutionalized populations, households and housing units. For the 2010 Census, there were no “XX” or “HH” ZCTAs assigned. Only five-digit ZCTAs were produced, and large unpopulated areas were excluded from the delineations. For the 2010 Census, there is no wall-to-wall national coverage for ZCTAs. Large water bodies and unpopulated land area such as national parks were excluded from the 2010 delineations, and for this reason the Census 2010 product does not have complete national coverage. This dataset is intended for researchers, students, policy makers, and the general public for reference and mapping purposes, and may be used for basic applications such as viewing, querying, and map output production, or to provide a basemap to support graphical overlays and analysis with other spatial data O'Neill, M. and California Office of Statewide Health Planning and Development. (2010). Census Zip Code Tabulation Areas, California, 2010. California Office of Statewide Health Planning and Development. Available at: http://purl.stanford.edu/dc841dq9031. The State of California, the California Health and Human Services Agency and the Office of Statewide Health Planning and Development make no representations or warranties regarding the accuracy of data or maps. The user will not seek to hold the State, the Agency or the Office liable under any circumstances for any damages with respect to any claim by the user or any third party on account of or arising from the use of data or maps. The user will cite the California Health and Human Services Agency and/or the Office as the original source of the data, but will clearly denote cases where the original data have been updated, modified, or in any way altered from the original condition. There are no restrictions on distribution of the data by users. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.

    View full record

  3. Title: Map 11: Amundsen Sea (Edition 1): Antarctica

    Contributors:

    Summary: See Edition 2 (https://maps.apps.pgc.umn.edu/antarctica/20/17) for the most recent version of this map.; Series: PGC 1:1,000,000 Air Operations Planning Map Series

    View full record

  4. Title: Map 13: Marie Byrd Land (Edition 1): Antarctica

    Contributors:

    Summary: See Edition 2 (https://maps.apps.pgc.umn.edu/antarctica/20/17) for the most recent version of this map.; Series: PGC 1:1,000,000 Air Operations Planning Map Series

    View full record

  5. Title: Map 12: Ellsworth Mountains (Edition 1): Antarctica

    Contributors:

    Summary: See Edition 2 (https://maps.apps.pgc.umn.edu/antarctica/20/17) for the most recent version of this map.; Series: PGC 1:1,000,000 Air Operations Planning Map Series

    View full record

  6. Title: Map 16: Victoria Land (Edition 1): Antarctica

    Contributors:

    Summary: See Edition 2 (https://maps.apps.pgc.umn.edu/antarctica/20/17) for the most recent version of this map.; Series: PGC 1:1,000,000 Air Operations Planning Map Series

    View full record

  7. Title: Solar Insolation, Minnesota] (2006-2012)

    Contributors:

    Summary: The Minnesota Solar Suitability Analysis attempts to provide solar insolation analysis for the entire State of Minnesota. As far as we are aware, it is the only project of its scale in existence; similar studies have been limited to metro areas or focus on rooftop insolation. The project's existence is feasible because of statewide, freely available aerial lidar coverage. And the commitment of the team to work long hours on this unfunded project. The project finds itself at the intersection of renewable energy, big data analysis, geospatial technology, and open data availability. This data provides a measure of incedent solar radiation as it is intercepted by the earth surface, or features (such as vegetation and buildings) standing above the earth surface. The data is intended to be used to assess the suitability of a site for solar panel (photovoltaic cell) installations. The analysis used to produce this dataset looks at geographic location, surface slope, surface aspect, and the effects of shading based on local topography and adjacent structures. A digital surface model was generated from raw LiDAR data. Then, using this DSM, an individual locations on a grid surface were assessed for the amount of direct and indirect radiation that reaches the surface. This analysis was conducted at a 1m resolution for the entire state of Minnesota.

    View full record

  8. Title: Digital Surface Model [Minnesota] (2006-2012)

    Contributors:

    Summary: A 1m resolution digital surface model that was generated from raw lidar data. This dataset was an intermediate product of a process to model potential solar insolation for the state of Minnesota. The Digital Surface Model (DSM) was created to represent the terrain and all object present on that terrain. This included buildings, tree cover, roads, and other natural and human-altered landscapes. In effect, the DSM is a three dimensional representation of Minnesota. It was generated using a Streaming Delauney Triangulation process through rapidlasso's LAStools software package. In this process, triangles are iteratively generated using nearby lidar returns and values for each point are determined by extracting interpolated elevation from the surface of the triangle. The result is a 1 meter resolution raster covering the state. Lidar is a form of active remote sensing technology that uses light pulses, most commonly in the near-infrared wavelengths, to collected surface elevation data. A laser scanner, mounted in an aircraft and combined with high-accuracy GPS, collects light returns that are interpolated into a point cloud. Each point represents one return from a laser pulse. The laser pulse has the ability to penetrate vegetation, multiple laser returns can be gathered for each pulse including the returns from below the vegetation.The accuracy of lidar returns allow for a unique, multi-faceted analytical dataset. The first point returns can be used to interpolate a topology of Minnesota that models the objects (i.e. building, trees, etc) and geography resting upon the terrain. The lidar point files for the state of Minnesota used in the study were collected between 2006 and 2012 through an intergovernmental initiative with the primary object of providing improved elevation data for flood mapping. In some regions, existing lidar data was acquired and transformed to new state standards. Areas where data did not exist or could not be transformed, were collected by contracted vendors. The composite data forms a seamless coverage of the state with a resolutions of at least 1.5 meters. Refer to metadata.html for full details.

    View full record

  9. Title: Edinburgh & Scotland : scale 1:10,000-550,000

    Contributors:

    Summary: Tourist street map of central districts. Relief on Scotland map shown by gradient tints and spot heights. Includes indexes and inset map of Shetland Islands. Panel title.

    View full record

  10. Title: Trenton public art map

    Contributors:

    Summary: In upper left-hand corner: Artworks presents Art all day Trenton. Title from verso. Index to public art map on verso.

    View full record

  11. Title: International travel maps, Barcelona, Spain, scale 1:12,500 : indexed

    Contributors:

    Summary: Ancillary maps: Barri Gotic & Ciutat Vella; Barceloneta; Metro map. With index of street names.

    View full record

  12. Title: Ground-water resources of Lucas County

    Contributors:

    Summary: Includes location map. Scale 1:62,500 Relief shown by contours and spot heights. by Michael Hallfrisch ; cartography, David S. Orr. "Total copies printed: 500."

    View full record

  13. Title: Map of Dublin and suburbs

    Contributors:

    Summary: Some buildings are shown pictorially.

    View full record

  14. Title: America siue India Nova ad magnae Gerardi Mercatoris aut Vniversalis imitationem in compendium redacta

    Contributors:

    Summary: 1 map: color; (In Mercator (Gerhard). Atlas. Ed. 10° (11th ed.) fol. Amsterodami, sumptibus H. Hondij, 1630); Insets: Golfo Mexi Cano; Haiti nunc Hispaniola; Cuba, and Title. Decorative border; Print version has date 1595 pencilled in title inset. Scale approximately 1:60,720,000 (W 180°--W 0°/N 90°--S 90°).

    View full record

  15. Title: Geology: Offshore of Tomales Point, California, 2010

    Contributors:

    Summary: This polygon shapefile depicts geologic features within the offshore area of Tomales Point, California. The morphology and the geology of the offshore part of the Offshore of Tomales Point map area result from the interplay between tectonics, sea-level rise, local sedimentary processes, and oceanography. The map area is cut by the northwest-trending San Andreas Fault, the right-lateral transform boundary between the North American and Pacific tectonic plates. The San Andreas strikes through Tomales Bay, the northern part of a linear valley that extends from Bolinas through Olema Valley to Bodega Bay, separating mainland California from the Point Reyes Peninsula. Onshore investigations indicate that this section of the San Andreas Fault has an estimated slip rate of about 17 to 25 mm/yr (Bryant and Lundberg, 2002; Grove and Niemi, 2005). The devastating Great 1906 California earthquake (M 7.8) is thought to have nucleated on the San Andreas Fault about 50 kilometers south of this map area offshore of San Francisco (e.g., Bolt, 1968; Lomax, 2005), with the rupture extending northward through the Offshore of Tomales Point map area to the south flank of Cape Mendocino (Lawson, 1908; Brown and Wolfe, 1972). The Point Reyes Peninsula is bounded to the south and west in the offshore by the north- and east-dipping Point Reyes Thrust Fault (McCulloch, 1987; Heck and others, 1990), which lies about 20 km west of Tomales Point. Granitic basement rocks are offset about 1.4 km on this thrust fault offshore of Point Reyes (McCulloch, 1987), and this uplift combined with west-side-up offset on the San Andreas Fault (Grove and Niemi, 2005) resulted in uplift of the Point Reyes Peninsula, including Tomales Point and the adjacent continental shelf. Grove and others (2010) reported uplift rates of as much as 1 mm/yr for the south flank of the Point Reyes Peninsula based on marine terraces, but reported no datable terrace surfaces that could constrain uplift for the flight of 4-5 terraces exposed farther north along Tomales Point. Because of this Quaternary uplift and relative lack of sediment supply from coastal watersheds, there is extensive rugged, rocky seafloor beneath the continental shelf in the Offshore of Tomales Point map area. Granitic rocks (unit Kg) on the seafloor are mapped on the basis of massive character, roughness, extensive fractures, and high backscatter (see Backscattter A to D--Offshore of Tomales Point, California, DS 781, for more information). Neogene sedimentary rocks (units Tl and Tu) commonly form distinctive "ribs," created by differential seafloor erosion of dipping beds of variable resistance. The more massive offshore outcrops of unit Tu in the southern part of the map area are inferred to represent more uniform lithologies. Slopes on the granitic seafloor (generally 1 to 1.3 degrees) are greater than those over sedimentary rock (generally about 0.5 to 0.6 degrees). Sediment-covered areas occur in gently sloping (less than about 0.6 degrees) mid-shelf environments west and north of Tomales Point, and at the mouth of Tomales Bay. Sediment supply is local, limited to erosion from local coastal bluffs and dunes, small coastal watersheds, and sediment flux out of the mouth of Tomales Bay. Shelf morphology and evolution largely reflects eustacy; sea level has risen about 125 to 130 m over about the last 21,000 years (for example, Lambeck and Chappell, 2001; Peltier and Fairbanks, 2005), leading to broadening of the continental shelf, progressive eastward migration of the shoreline and wave-cut platform, and associated transgressive erosion and deposition. Given present exposure to high wave energy, modern nearshore to mid-shelf sediments are mostly sand (unit Qms) and a mix of sand, gravel, and cobbles (units Qmsc and Qmsd). These sediments are distributed between rocky outcrops at water depths of as much as 65 m (see below). The more coarse-grained sands and gravels (units Qmsc and Qmsd) are primarily recognized on the basis of bathymetry and high backscatter. Unit Qmsd forms erosional lags in scoured depressions that are bounded by relatively sharp contacts with bedrock or sharp to diffuse contacts with units Qms and Qmsc. These scoured depressions are typically a few tens of centimeters deep and range in size from a few 10's of sq m to more than one sq km. Similar unit Qmsd scour depressions are common along this stretch of the California coast (see, for example, Cacchione and others, 1984; Hallenbeck and others, 2012) where surficial offshore sandy sediment is relatively thin (thus unable to fill the depressions) due to both lack of sediment supply and to erosion and transport of sediment during large northwest winter swells. Such features have been referred to as rippled-scour depressions (see, for example, Cacchione and others, 1984) or sorted bedforms (see, for example, Goff and others, 2005; Trembanis and Hume, 2011). Although the general areas in which both unit Qmsd scour depressions and surrounding mobile sand sheets occur are not likely to change substantially, the boundaries of the individual Qmsd depressions are likely ephemeral, changing seasonally and during significant storm events. Unit Qmsf consists primarily of mud and muddy sand and is commonly extensively bioturbated. The location of the inboard contact at water depths of about 65 m is based on meager sediment sampling and photographic data and the inference that if must lie offshore of the outer boundary of coarse-grained units Qmsd and Qmsc. This is notably deeper than the inner contact of unit Qmsf offshore of the nearby Russian River (about 50 m; Klise, 1983) which could may reflect both increased wave energy and significantly decreased supply of muddy sediment. There are two areas of high-backscatter, rough seafloor at water depths of 65 to 70 m west of northern Tomales Point. These areas are notable in that each includes several small (less than about 20,000 sq m), randomly distributed to northwest-trending, irregular "mounds," with as much as 1 m of positive relief above the seafloor (unit Qsr). Seismic-reflection data (see field activity S-15-10-NC) reveal this lumpy material rests on several meters of latest Pleistoce to Holocene sediment and is thus not bedrock outcrop. Rather, it seems likely that this material is marine debris, possibly derived from one (or more) of the more than 60 shipwrecks that have occurred offshore of the Point Reyes Peninsula between 1849 and 1940 (National Park Service, 2012). It is also conceivable that this lumpy terrane consists of biological "hardgrounds" Units Qsw, Qstb, Qdtb, and Qsdtb comprise sediments in Tomales Bay. Anima and others (2008) conducted a high-resolution bathymetric survey of Tomales Bay and noted that strong tidal currents at the mouth of the bay had created a large field of sandwaves, dunes, and flats (unit Qsw). Unit Qkdtb is a small subaqueous sandy delta deposited at the mouth of Keys Creek, the largest coastal watershed draining into this northern part of Tomales Bay. Unit Qstb occurs south of units Qsw and Qdtb, and comprises largely flat seafloor underlain by mixed sand and silt. Unit Qdtb consists of depressions within the sedimentary fill of Tomales Bay. These depressions commonly occur directly offshore of coastal promontories, cover as much as 74,000 sq m, and are as deep as 9 m. Map unit polygons were digitized over underlying 2-meter base layers developed from multibeam bathymetry and backscatter data (see Bathymetry--Offshore of Tomales Point, California and Backscattter A to D--Offshore of Tomales Point, California, DS 781). The bathymetry and backscatter data were collected between 2006 and 2010. A map that shows these data is published in Open-File Report 2015-1088, "California State Waters Map Series--Offshore of Tomales Point, California." This layer is part of USGS Data Series 781. In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP) 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. CSMP has divided coastal California into 110 map blocks, each to be published individually as United States Geological Survey Open-File Reports (OFRs) or Scientific Investigations Maps (SIMs) at a scale of 1:24,000. Maps display seafloor morphology and character, identify potential marine benthic habitats and illustrate both the seafloor geology and shallow (to about 100 m) subsurface geology. Data layers for bathymetry, bathymetric contours, acoustic backscatter, seafloor character, potential benthic habitat and offshore geology were created for each map block, as well as regional-scale data layers for sediment thickness, depth to transition, transgressive contours, isopachs, predicted distributions of benthic macro-invertebrates and visual observations of benthic habitat from video cruises over the entire state. This coverage can be used to to aid in assessments and mitigation of geologic hazards in the coastal region and to provide sufficient geologic information for land-use and land-management decisions both onshore and offshore. These data are intended for science researchers, students, policy makers, and the general public. This information is not intended for navigational purposes.The data can be used with geographic information systems (GIS) software to display geologic and oceanographic information. Hartwell, S.R., Johnson, S.Y., and Manson, M.W. (2014). Geology: Offshore of Tomales Point, California, 2010. California State Waters Map Series Data Catalog: U.S. Geological Survey Data Series 781. Available at: http://purl.stanford.edu/zg934rd8487. Map political location: San Mateo County, California Compilation scale: 1:24,000 Base maps used are hillshades generated from IfSAR, LiDAR, and multibeam mapping both onshore and offshore (see Bathymetry Hillshade--Offshore of Tomales Point, California, DS 781, for more information). References Cited Anima, R. A., Chin, J.L., Finlayson, D.P., McGann, M.L., and Wong, F.L., 2008, Interferometric sidescan bathymetry, sediment and foraminiferal analyses; a new look at Tomales Bay, California: U.S. Geological Survey Open-File Report 2008 - 1237, 33 p. Brown, R.D., Jr., and Wolfe, E.W., 1972, Map showing recently active breaks along the San Andreas Fault between Point Delgada and Bolinas Bay, California: U.S. Geological Survey Miscellaneous Investigations Map I-692, scale 1:24,000. Bryant, W.A., and Lundberg, M.M., compilers, 2002, Fault number 1b, San Andreas fault zone, North Coast section, in Quaternary fault and fold database of the United States: U.S. Geological Survey website, accessed April 4, 2013 at http://earthquakes.usgs.gov/hazards/qfaults. Cacchione, D.A., Drake, D.E., Grant, W.D., and Tate, G.B., 1984, Rippled scour depressions of the inner continental shelf off central California: Journal of Sedimentary Petrology, v. 54, p. 1,280-1,291. Grove, K., and Niemi, T.M., 2005, Late Quaternary deformation and slip rates in the northern San Andreas fault zone at Olema Valley, Marin County, California: Tectonophysics, v. 401, p. 231-250. Grove, K, Sklar, L.S., Scherer, A.M., Lee, G., and Davis, J., 2010, Accelerating and spatially-varying crustal uplift and its geomorphic expression, San Andreas fault zone north of San Francisco, California: Tectonophysics, v. 495, p. 256-268. Klise, D.H., 1984, Modern sedimentation on the California continental margin adjacent to the Russian River: M.S. thesis, San Jose State University, 120 p. Hallenbeck, T.R., Kvitek, R.G., and Lindholm, J., 2012, Rippled scour depressions add ecologically significant heterogeneity to soft-bottom habitats on the continental shelf: Marine Ecology Progress Series, v. 468, p. 119-133. Lambeck, K., and Chappell, J., 2001, Sea level change through the last glacial cycle: Science, v. 292, p. 679-686, doi: 10.1126/science.1059549. Lawson, A.C., ed., 1908, The California earthquake of April 18, 1906, Report of the State Earthquake Investigation Commission: Carnegie Institution of Washington Publication 87, v. 1, 1451 p. and atlas. Lomax, A., 2005, A reanalysis of the hypocentral location and related observations for the Great 1906 California earthquake: Bulletin of the Seismological Society of America, v. 95, p. 861-877. 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. National Park Service, 2012, Shipwrecks at Point Reyes, accessed May 1, 2013 at: http://www.nps.gov/pore/historyculture/upload/map_shipwrecks.pdf This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.

    View full record

  16. Title: Folds: Offshore of Tomales Point, California, 2010

    Contributors:

    Summary: This line shapefile depicts geologic folds within the offshore area of Tomales Point, California. The Point Reyes Peninsula is bounded to the south and west in the offshore by the north- and east-dipping Point Reyes Thrust Fault (McCulloch, 1987; Heck and others, 1990), which lies about 20 km west of Tomales Point. Granitic basement rocks are offset about 1.4 km on this thrust fault offshore of Point Reyes (McCulloch, 1987), and this uplift combined with west-side-up offset on the San Andreas Fault (Grove and Niemi, 2005) resulted in uplift of the Point Reyes Peninsula, including Tomales Point and the adjacent continental shelf. Grove and others (2010) reported uplift rates of as much as 1 mm/yr for the south flank of the Point Reyes Peninsula based on marine terraces, but reported no datable terrace surfaces that could constrain uplift for the flight of 4-5 terraces exposed farther north along Tomales Point. 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. A map that shows these data is published in Open-File Report 2015-1088, "California State Waters Map Series--Offshore of Tomales Point, California." This layer is part of USGS Data Series 781. In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP) 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. CSMP has divided coastal California into 110 map blocks, each to be published individually as United States Geological Survey Open-File Reports (OFRs) or Scientific Investigations Maps (SIMs) at a scale of 1:24,000. Maps display seafloor morphology and character, identify potential marine benthic habitats and illustrate both the seafloor geology and shallow (to about 100 m) subsurface geology. Data layers for bathymetry, bathymetric contours, acoustic backscatter, seafloor character, potential benthic habitat and offshore geology were created for each map block, as well as regional-scale data layers for sediment thickness, depth to transition, transgressive contours, isopachs, predicted distributions of benthic macro-invertebrates and visual observations of benthic habitat from video cruises over the entire state. This coverage can be used to to aid in assessments and mitigation of geologic hazards in the coastal region and to provide sufficient geologic information for land-use and land-management decisions both onshore and offshore. These data are intended for science researchers, students, policy makers, and the general public. This information is not intended for navigational purposes.The data can be used with geographic information systems (GIS) software to display geologic and oceanographic information. Hartwell, S.R., Johnson, S.Y., and Manson, M.W. (2014). Folds: Offshore of Tomales Point, California, 2010. California State Waters Map Series Data Catalog: U.S. Geological Survey Data Series 781. Available at: http://purl.stanford.edu/jf036dx3445. Map political location: San Mateo County, California Compilation scale: 1:24,000 Base maps used are hillshades generated from IfSAR, LiDAR, and multibeam mapping both onshore and offshore (see Bathymetry Hillshade--Offshore of Tomales Point, California, DS 781, for more information). . References Cited Grove, K., and Niemi, T.M., 2005, Late Quaternary deformation and slip rates in the northern San Andreas fault zone at Olema Valley, Marin County, California: Tectonophysics, v. 401, p. 231-250. Grove, K, Sklar, L.S., Scherer, A.M., Lee, G., and Davis, J., 2010, Accelerating and spatially-varying crustal uplift and its geomorphic expression, San Andreas fault zone north of San Francisco, California: Tectonophysics, v. 495, p. 256-268. 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. 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. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.

    View full record

  17. Title: Geology: Offshore of Fort Ross, California, 2009

    Contributors:

    Summary: This polygon shapefile represents geologic features in the offshore area of Fort Ross, California. The morphology and the geology of the offshore part of the Offshore of Fort Ross map area result from the interplay between local sedimentary processes, oceanography, sea-level rise, and tectonics. The nearshore seafloor in the northern half of the map area is characterized by rocky outcrops of Tertiary sedimentary rocks (units Tgr and Tsm). This rugged nearshore zone and the inner shelf (to water depths of about 50 m) typically dip seaward about 1.5 to 2.5 degrees, whereas the mid-shelf within State Waters (about 50 to 85 m) dips more gently, about 0.4 degrees. In contrast, the nearshore to mid shelf in the southern half of the map area lies directly offshore of the mouth of the Russian River and has a more gentle, uniform dip, about 0.45 to 0.55 degrees, out to water depths of about 70 m at the outer limit of State Waters. A significant amount of the Russian River sediment load, estimated at about 900,000 metric tons/yr by Farnsworth and Warrick (2007) is deposited offshore of the river mouth, contributing to the noted north-to-south contrast in bathymetric slope. On a larger geomorphic scale, sea level has risen about 125 to 130 m over about the last 21,000 years (for example, Lambeck and Chappell, 2001; Peltier and Fairbanks, 2005), leading to broadening of the continental shelf, progressive eastward migration of the shoreline and wave-cut platform, and associated transgressive erosion and deposition. Tectonic influences impacting shelf geomorphology and geology are primarily related to the active San Andreas Fault system (see below). Given exposure to high wave energy, modern nearshore to inner-shelf sediments north of the mouth of the Russian River are mostly sand (unit Qms) and a mix of sand, gravel, and cobbles (units Qmsc and Qmsd). The more coarse-grained sands and gravels (units Qmsc and Qmsd) are primarily recognized on the basis of bathymetry and high backscatter. Both Qmsc and Qmsd typically have abrupt landward contacts with bedrock (units Tgr, Tsm, Tkfs, fsr) and form irregular to lenticular exposures that are commonly elongate in the shore-normal direction. Contacts between units Qmsc and Qms are typically gradational. Unit Qmsd forms erosional lags in scoured depressions that are bounded by relatively sharp and less commonly diffuse contacts with unit Qms horizontal sand sheets. These depressions are typically a few tens of centimeters deep and range in size from a few 10's of sq m to more than one sq km. Similar Qmsd scour depressions are common along this stretch of the California coast (see, for example, Cacchione and others, 1984; Hallenbeck and others, 2012) where surficial offshore sandy sediment is relatively thin (thus unable to fill the depressions) due to both lack of sediment supply and to erosion and transport of sediment during large northwest winter swells. Such features have been referred to as "rippled-scour depressions" (see, for example, Cacchione and others, 1984) or "sorted bedforms" (see, for example, Goff and others, 2005; Trembanis and Hume, 2011). Although the general areas in which both Qmsd scour depressions and surrounding mobile sand sheets occur are not likely to change substantially, the boundaries of the individual Qmsd depressions are likely ephemeral, changing seasonally and during significant storm events. Unit Qmsf lies offshore of unit Qms, and consists primarily of mud and muddy sand and is commonly extensively bioturbated. The water depth of the transition from sand-dominated marine sediment (unit Qms) to mud-dominated marine sediment (Qmsf) increases from about 45 to 50 m directly offshore of the mouth of the Russian River to as much as about 60 m adjacent to the rocky outcrops along the northern map boundary. This change is clearly related to the large amount of fine sediment load carried by the Russian River, which feeds a widespread, mid-shelf, mud belt that extends along the mid-shelf from Point Arena to Point Reyes (Klise, 1983; Drake and Cacchione, 1985; Demirpolat, 1991). Map unit polygons were digitized over underlying 2-meter base layers developed from multibeam bathymetry and backscatter data (see Bathymetry--Offshore Fort Ross, California and Backscattter A to C--Offshore Fort Ross, California, DS 781, for more information). The bathymetry and backscatter data were collected between 2006 and 2009. This layer is part of USGS Data Series 781. In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP) 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. CSMP has divided coastal California into 110 map blocks, each to be published individually as United States Geological Survey Open-File Reports (OFRs) or Scientific Investigations Maps (SIMs) at a scale of 1:24,000. Maps display seafloor morphology and character, identify potential marine benthic habitats and illustrate both the seafloor geology and shallow (to about 100 m) subsurface geology. Data layers for bathymetry, bathymetric contours, acoustic backscatter, seafloor character, potential benthic habitat and offshore geology were created for each map block, as well as regional-scale data layers for sediment thickness, depth to transition, transgressive contours, isopachs, predicted distributions of benthic macro-invertebrates and visual observations of benthic habitat from video cruises over the entire state. These data are intended for science researchers, students, policy makers, and the general public. This information is not intended for navigational purposes.The data can be used with geographic information systems (GIS) software to display geologic and oceanographic information. Additionally, this coverage can provide a geologic map for the public and geoscience community to aid in assessments and mitigation of geologic hazards in the coastal region and sufficient geologic information for land-use and land-management decisions both onshore and offshore. This information is not intended for navigational purposes. Johnson, S.Y., Hartwell, S.R., and Manson, M.W. (2014). Geology: Offshore of Fort Ross, California, 2009. California State Waters Map Series Data Catalog: U.S. Geological Survey Data Series 781. Available at: http://purl.stanford.edu/vd660hx5851. Map political location: San Mateo County, California Compilation scale: 1:24,000 Base maps used are hillshades generated from IfSAR, LiDAR, and multibeam mapping both onshore and offshore (see Bathymetry--Offshore of Fort Ross Map Area, California). . References Cited Cacchione, D.A., Drake, D.E., Grant, W.D., and Tate, G.B., 1984, Rippled scour depressions of the inner continental shelf off central California: Journal of Sedimentary Petrology, v. 54, p. 1,280-1,291. Demirpolat, S., 1991, Surface and near-surface sediments from the continental shelf off the Russian River, northern California: Marine Geology, v. 99, p. 163-173. Drake, D.E., and Cacchione, D.A., 1985, Seasonal variation in sediment transport on the Russian River shelf, California: Continental Shelf Research, v. 14, p. 495-514. Farnsworth, K.L., and Warrick, J.A., 2007, Sources, dispersal, and fate of fine sediment supplied to coastal California: U.S. Geological Survey Scientific Investigations Report 2007-5254, 77 p. Goff, J.A., Mayer, L.A., Traykovski, P., Buynevich, I., Wilkens, R., Raymond, R., Glang, G., Evans, R.L., Olson, H., and Jenkins, C., 2005, Detailed investigations of sorted bedforms or "rippled scour depressions", within the Marthaâs Vineyard Coastal Observatory, Massachusetts: Continental Shelf Research, v. 25, p. 461-484. Hallenbeck, T.R., Kvitek, R.G., and Lindholm, J., 2012, Rippled scour depressions add ecologically significant heterogeneity to soft-bottom habitats on the continental shelf: Marine Ecology Progress Series, v. 468, p. 119-133. Klise, D.H., 1983, Modern sedimentation on the California continental margin adjacent to the Russian River: M.S. thesis, San Jose State University, 120 p. Lambeck, K., and Chappell, J., 2001, Sea level change through the last glacial cycle: Science, v. 292, p. 679-686, doi: 10.1126/science.1059549. Peltier, W.R., and Fairbanks, R.G., 2005, Global glacial ice volume and Last Glacial Maximum duration from an extended Barbados sea level record: Quaternary Science Reviews, v. 25, p. 3,322-3,337. Trembanis, A.C., and Hume, T.M., 2011, Sorted bedforms on the inner shelf off northeastern New Zealand-Spatiotemporal relationships and potential paleo-environmental implications: Geo-Marine Letters, v. 31, p. 203-214. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.

    View full record

  18. Title: Faults: Offshore of San Francisco, California, 2010

    Contributors:

    Summary: This line shapefile contains fault lines within the offshore area of San Francisco, California. The map area straddles the right-lateral transform boundary between the North American and Pacific plates and is cut by several active faults that cumulatively form a distributed shear zone, including the San Andreas Fault, the eastern strand of the San Gregorio Fault, the Golden Gate Fault, and the Potato Patch Fault (Bruns and others, 2002; Ryan and others, 2008). These faults are covered by Holocene sediments (mostly units Qms, Qmsb, Qmst) with no seafloor expression, and are mapped using seismic-reflection data (see field activities S-15-10-NC and F-2-07-NC). The San Andreas Fault is the primary plate-boundary structure and extends northwest across the map area; it intersects the shoreline 10 km north of the map area at Bolinas Lagoon, and 3 km south of the map area at Mussel Rock. This section of the San Andreas Fault has an estimated slip rate of 17 to 24 mm/yr (U.S. Geological Survey, 2010), and the devastating Great 1906 California earthquake (M 7.8) is thought to have nucleated on the San Andreas a few kilometers offshore of San Francisco within the map area (Bolt, 1968; Lomax, 2005). The San Andreas Fault forms the boundary between two distinct basement terranes, Upper Jurassic to Lower Cretaceous rocks of the Franciscan Complex to the east, and Late Cretaceous granitic and older metamorphic rocks of the Salinian block to the west. Franciscan Complex rocks (unit KJf, undivided) form seafloor outcrops at and north of Point Lobos adjacent to onland exposures. The Franciscan is divided into 13 different units for the onshore portion of this geologic map based on different lithologies and ages, but the unit cannot be similarly divided in the offshore because of a lack of direct observation and (or) sampling. Faults were primarily mapped by interpretation of seismic reflection profile data (see field activities S-15-10-NC and F-2-07-NC). The seismic reflection profiles were collected between 2007 and 2010. A map that shows these data is published in Open-File Report 2015-1068, "California State Waters Map Series--Offshore of San Francisco, California." This layer is part of USGS Data Series 781. In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP) 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. CSMP has divided coastal California into 110 map blocks, each to be published individually as United States Geological Survey Open-File Reports (OFRs) or Scientific Investigations Maps (SIMs) at a scale of 1:24,000. Maps display seafloor morphology and character, identify potential marine benthic habitats and illustrate both the seafloor geology and shallow (to about 100 m) subsurface geology. Data layers for bathymetry, bathymetric contours, acoustic backscatter, seafloor character, potential benthic habitat and offshore geology were created for each map block, as well as regional-scale data layers for sediment thickness, depth to transition, transgressive contours, isopachs, predicted distributions of benthic macro-invertebrates and visual observations of benthic habitat from video cruises over the entire state. This coverage can be used to to aid in assessments and mitigation of geologic hazards in the coastal region and to provide sufficient geologic information for land-use and land-management decisions both onshore and offshore. These data are intended for science researchers, students, policy makers, and the general public. This information is not intended for navigational purposes.The data can be used with geographic information systems (GIS) software to display geologic and oceanographic information. Greene, H.G., Johnson, S.Y., Manson, M.W., Hartwell, S.R., Endris, C.A., and Bruns, T.R. (2014). Faults: Offshore of San Francisco, California, 2010. California State Waters Map Series Data Catalog: U.S. Geological Survey Data Series 781. Available at: http://purl.stanford.edu/xw411td7423. Map political location: San Mateo County, California Compilation scale: 1:24,000 Base maps used are hillshades generated from IfSAR, LiDAR, and multibeam mapping both onshore and offshore (see Bathymetry Hillshade--Offshore San Francisco, California, DS 781, for more information). . References Cited Bolt, B.A., 1968, The focus of the 1906 California earthquake: Bulletin of the Seismological Society of America, v. 58, p. 457-471. 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. Lomax, A., 2005, A reanalysis of the hypocentral location and related observations for the Great 1906 California earthquake: Bulletin of the Seismological Society of America, v. 95, p. 861-877. 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, 429 (1-2), p. 209-224. 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/. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.

    View full record

  19. Title: Geology: Offshore of San Francisco, California, 2010

    Contributors:

    Summary: This polygon shapefile depicts geological features within the offshore area of San Francisco, California. The map area includes the Golden Gate inlet which connects the Pacific Ocean and San Francisco Bay. San Francisco Bay, the largest estuary on the U.S. west coast, is located at the mouth of the Sacramento and San Joaquin rivers and drains over 40 percent of the state of California. The large surface area of the bay and diurnal tidal range of 1.78 m creates an enormous tidal prism (about 2 billion cu m) and strong tidal currents, commonly exceeding 2.5 m/s (Barnard and others, 2006a, 2006b, 2007). Acceleration of these currents through the constricted inlet has led to scouring of a bedrock channel that has a maximum depth of 113 m. Large fields of sand waves (Barnard and others, 2007) (unit Qmsw) have formed both west and east of this channel as flow expands and tidal currents decelerate. Active tidally influenced map units inside San Francisco Bay also include sand-dominated deposits (unit Qbs) and more coarse-grained sand, gravel, and pebble deposits (unit Qbsc). Sand wave fields resulting from tidal flow are also present in the nearshore along the Pacific Coast, both north and south of the Golden Gate inlet. The sand wave fields appear to be variably mobilized by both ebb and flood tides, but the presence of a large (~150 sq km) ebb-tidal delta at the mouth of the bay west of the inlet indicates net sediment transport has been to the west. The ebb-tidal delta west of the Golden Gate inlet is mapped as two units. The inner part of the delta (unit Qmst) comprises a semi-circular, inward-sloping (i.e., toward the Golden Gate inlet), sandy seafloor at water depths of about 12 to 24 m. This inner delta has a notably smooth surface, indicating sediment transport and deposition under different flow regimes (defined by tidal current strength and depth) than those in which the sand waves formed and are maintained. Further deceleration of tidal currents beyond the inner delta has led to development of a large, shoaling (about 8 to 12 m water depth), horse-shoe shaped, delta-mouth bar (unit Qmsb). This feature (the "San Francisco Bar") surrounds the inner delta, and its central crest is cut by a dredged shipping channel that separates the nothern and southern parts of the bar, the "North Bar" and "South Bar," respectively. The San Francisco Bar is shaped by both tidal currents and waves, which regularly exceed 6 m in height on the continental shelf during major winter storms (Barnard and others, 2007). This mix of tidal and wave influence results in a variably hummocky, mottled, and rilled seafloor, and this surface texture is used as a primary criteria for mapping the unit and defining its boundaries. Outside the San Francisco Bar to the limits of the map area, the notably flat shelf (less than 0.2 degrees) and the nearshore are wave-dominated and characterized by sandy marine sediment (unit Qms). Local zones of wave-winnowed (?) coarser sediment (unit Qmsc) indicated by high backscatter occur along the coast offshore Ocean Beach. Unit Qmsc is also mapped inside and at the mouth of the Golden Gate inlet where it presumably results from winnowing by strong tidal currents. Coarser sediment also occurs as winnowed lags in rippled scour depressions (unit Qmss), recognized on the basis of high-resolution bathymetry and backscatter. These depressions are typically a few tens of centimeters deep and are bounded by mobile sand sheets (for example, Cacchione and others, 1984). This unit occurs primarily in the nearshore south of the Golden Gate inlet offshore of Ocean Beach (water depth less than 13 m) and north of the inlet offshore Muir Beach (water depth less than 17 m). Artificial seafloor (unit af) has several distinct map occurrences: (1) sites of active sand mining inside San Francisco Bay; (2) the dredged shipping channel at the central crest of the San Francisco Bar; (3) the sewage outfall pipe, associated rip rap, and surrounding scour channel offshore Ocean Beach; and (4) the location of a former waste disposal site about 2.5 km offshore Point Lobos. Although the map shows the areas in which several active sedimentary units (Qmsw, Qmst, Qmsb, Qms, Qmsc, Qmss, Qbsm, Qbsc) presently occur, it is important to note that map units and contacts are dynamic and ephemeral, likely to change during large storms, and on seasonal to decadal scales based on changing external forces such as weather, climate, sea level, and sediment supply. Dallas and Barnard (2011) have noted, for example, that the ebb-tidal delta has dramatically shrunk since 1873 when the first bathymetric survey of the area was undertaken. They document an approximate 1 km landward migration of the crest of the San Francisco Bar, which they attribute to a reduction in the tidal prism of San Francisco Bay and a decrease in coastal sediment. Map unit polygons were digitized over underlying 2-meter base layers developed from multibeam bathymetry and backscatter data. The bathymetry and backscatter data were collected between 2006 and 2010. A map that shows these data is published in Open-File Report 2015-1068, "California State Waters Map Series--Offshore of San Francisco, California." This layer is part of USGS Data Series 781. In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP) 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. CSMP has divided coastal California into 110 map blocks, each to be published individually as United States Geological Survey Open-File Reports (OFRs) or Scientific Investigations Maps (SIMs) at a scale of 1:24,000. Maps display seafloor morphology and character, identify potential marine benthic habitats and illustrate both the seafloor geology and shallow (to about 100 m) subsurface geology. Data layers for bathymetry, bathymetric contours, acoustic backscatter, seafloor character, potential benthic habitat and offshore geology were created for each map block, as well as regional-scale data layers for sediment thickness, depth to transition, transgressive contours, isopachs, predicted distributions of benthic macro-invertebrates and visual observations of benthic habitat from video cruises over the entire state. This coverage can be used to to aid in assessments and mitigation of geologic hazards in the coastal region and to provide sufficient geologic information for land-use and land-management decisions both onshore and offshore. These data are intended for science researchers, students, policy makers, and the general public. This information is not intended for navigational purposes.The data can be used with geographic information systems (GIS) software to display geologic and oceanographic information. Greene, H.G., Johnson, S.Y., Manson, M.W., Hartwell, S.R., Endris, C.A., and Bruns, T.R. (2014). Geology: Offshore of San Francisco, California, 2010. California State Waters Map Series Data Catalog: U.S. Geological Survey Data Series 781. Available at: http://purl.stanford.edu/kn414qm4080. Map political location: San Mateo County, California Compilation scale: 1:24,000 Base maps used are hillshades generated from IfSAR, LiDAR, and multibeam mapping both onshore and offshore (see Bathymetry Hillshade--Offshore San Francisco, California, DS 781, for more information). References Cited Barnard, P.L., Eshelman, J., Erikson, L., and Hanes, D.M., 2007, Coastal processes study at Ocean Beach, San Francisco, CA: Summary of data collection 2004-2006: U.S. Geological Survey Open-File Report 2007-1217, 165 p. Barnard, P.L., Hanes, D.M., Kvitek, R.G., and Iampietro, P.J., 2006a, Sand waves at the mouth of San Francisco Bay, California: U.S. Geological Survey Scientific Investigations Map 2944, 5 sheets. Barnard, P.L., Hanes, D.M., Rubin, D.M., and Kvitek, R.G., 2006b, Giant sand waves at the mouth of San Francisco Bay: EOS, V. 87, p. 285, 289. Cacchione, D.A., Drake, D.E., Grant, W.D., and Tate, G.B., 1984. Rippled scour depressions of the inner continental shelf off central California: Journal of Sedimentary Petrology, v 54, p. 1280-1291. Dallas, K.L., and Barnard, P.L., 2011, Anthropogenic influences on shoreline and nearshore evolution in the San Francisco coastal system: Estuarine Coastal and Shelf Science, v. 92, p. 195-204. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.

    View full record

  20. Title: Geology: Offshore of Pacifica, California, 2010

    Contributors:

    Summary: This polygon shapefile depictss geologic features in the offshore area of Pacifica, California. The continental shelf within California's State waters in the Pacifica area is shallow (water depths of 0 to about 40 m) and flat continental shelf with a very gentle (less than 0.5 degrees) offshore dip. The morphology and geology of this shelf result from the interplay between local tectonics, sea-level rise, sedimentary processes, and oceanography. Tectonic influences are related to local faulting and uplift (see below). Sea level has risen about 125 to 130 m over the last about 21,000 years (for example, Lambeck and Chappel, 2001; Gornitz, 2009), leading to progressive eastward migration (a few tens of km) of the shoreline and wave-cut platform, and associated transgressive erosion and deposition (for example, Catuneanu, 2006). The Offshore of Pacifica map area is now mainly an open shelf that is subjected to full, and sometimes severe, Pacific Ocean wave energy and strong currents. Most of the offshore map area is covered by marine sediments; artificial fill (unit af) occurs only at the site of the Pacifica Pier. Given their relatively shallow depths and exposure to high wave energy, modern shelf deposits are mostly sand (unit Qms). More coarse-grained sands and gravels (units Qmss and Qmsc) are primarily recognized on the basis of bathymetry and high backscatter (Bathymetry--Offshore of Pacifica map area, California, and Backscatter--Offshore of Pacifica map area, California). Unit Qmsc occurs as nearshore bars (less than 12 m water depth) for about two kilometers north of Mussel Rock and more locally offshore Pacifica, and in two isolated patches farther offshore at about 25 m water depth. Unit Qmss forms erosional lags in features known as ârippled scour depressionsâ (for example, Cacchione and others, 1984) or âsorted bedformsâ (for example, Trembanis and Hume, 2011), at water depths of about 15 to 25 m, in contact with offshore bedrock uplifts and unit Qms. Such features are common along this stretch of the California coast where offshore sandy sediment can be relatively thin (thus unable to fill the depressions) due to both lack of sediment supply from rivers and to significant sediment erosion and offshore transport during large winter storms. Although the general areas in which both unit Qmss scour depressions and unit Qmsc bars occur are not likely to change substantially, the boundaries of the unit(s) are likely ephemeral, changing seasonally and during significant storm events. Areas where shelf sediments form thin (less than 2 m) veneers over low relief bedrock of the Franciscan Complex (see below) occur in the northern half of the map and are mapped as unit Qms/KJf. This hybrid unit is recognized and delineated based on the combination of flat relief, continuity with moderate to high relief onshore or offshore bedrock outcrops, high-resolution seismic-reflection data, and in some cases moderate to high backscatter. The thin sediment layer is regarded as ephemeral and dynamic, and may or may not be present at a specific location based on storms, seasonal to annual patterns of sediment movement, or longer-term climate cycles. In a nearby, similarly high-energy setting, Storlazzi and others (2011) have described seasonal burial and exhumation of submerged bedrock in northern Monterey Bay. Offshore bedrock exposed at the seafloor is mapped as Jurassic and Cretaceous Franciscan Complex, undivided (unit KJf); Cretaceous granite (unit Kgr); Tertiary and (or) Cretaceous rock, undivided (unit TKu); unnamed sansdstone, shale and conglomerate of Paleocene age (unit Tss); and the Upper Miocene and Pliocene Purisima Formation (unit Tp). These units are delineated by extending outcrops and trends from mapped onshore geology and from their distinctive surface textures as revealed by high-resolution bathymetry (Bathymetry--Offshore of Pacifica map area, California). Purisima Formation outcrops in the southernmost part of the offshore map area form distinctive "ribs," caused by differential erosion of variably resistant, interbedded lithologies (for example, sandstone and mudstone). In contrast, granitic rocks have a densely cross-fractured, rough surface texture, and both the Franciscan Complex and the unnamed Paleocene sedimentary unit have a more masssive, irregular, and smoother surface texture. Purisima Formation outcrops occur in water as deep as 35 m, whereas other bedrock units occur in shallower (less than 20 m) water depths, most commonly adjacent to coastal points underlain by bedrock (for example, Pedro Point and Montara Point). Map unit polygons were digitized over underlying 2-meter base layers developed from multibeam bathymetry and backscatter data. The bathymetry and backscatter data were collected between 2006 and 2010. A map which shows these data is published in Scientific Investigations Map 3302, "California State Waters Map Series--Offshore of Coal Oil Point, California." This layer is part of USGS Data Series 781. In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP) 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. CSMP has divided coastal California into 110 map blocks, each to be published individually as United States Geological Survey Open-File Reports (OFRs) or Scientific Investigations Maps (SIMs) at a scale of 1:24,000. Maps display seafloor morphology and character, identify potential marine benthic habitats and illustrate both the seafloor geology and shallow (to about 100 m) subsurface geology. Data layers for bathymetry, bathymetric contours, acoustic backscatter, seafloor character, potential benthic habitat and offshore geology were created for each map block, as well as regional-scale data layers for sediment thickness, depth to transition, transgressive contours, isopachs, predicted distributions of benthic macro-invertebrates and visual observations of benthic habitat from video cruises over the entire state. These data are intended for science researchers, students, policy makers, and the general public. This information is not intended for navigational purposes.The data can be used with geographic information systems (GIS) software to display geologic and oceanographic information. Additionally, this coverage can provide a geologic map for the public and geoscience community to aid in assessments and mitigation of geologic hazards in the coastal region and sufficient geologic information for land-use and land-management decisions both onshore and offshore. This information is not intended for navigational purposes. Greene, H.G., Hartwell, S.R., Manson, M.W., Johnson, S.Y., Dieter, B.E., Phillips, E.L., and Watt, J.T. (2014). Geology: Offshore of Pacifica, California, 2010. California State Waters Map Series Data Catalog: U.S. Geological Survey Data Series 781. Available at: http://purl.stanford.edu/zg982fx5597. Map political location: San Mateo County, California Compilation scale: 1:24,000 Base maps used are hillshades generated from IfSAR, LiDAR, and multibeam mapping both onshore and offshore (Bathymetry--Offshore of Pacifica map area, California, DS 781, for more information). References Cited Cacchione, D.A., Drake, D.E., Grant, W.D., and Tate, G.B., 1984. Rippled scour depressions of the inner continental shelf off central California: Journal of Sedimentary Petrology, v 54, p. 1280-1291. Catuneanu, O., 2006, Principles of Sequence Stratigraphy: Amsterdam, Elsevier, 375 p. Gornitz, V., 2009, Sea level change, post-glacial, in Gornitz, V., ed., Encyclopedia of Paleoclimatology and Ancient Environments: Encyclopedia of Earth Sciences Series. Springer, pp. 887-893. Lambeck, K., and Chappell, J., 2001, Sea level change through the last glacial cycle: Science, v. 292, p. 679-686. Trembanis, A.C., and Hume, T.M., 2011, Sorted bedforms on the inner shelf off northeastern New Zealand: spatiotemporal relationships and potential paleo-evironmental implications: Geo-Marine Letters, v. 31, p. 203-214. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.

    View full record

Need help?

Ask GIS