Geology--Offshore of Coal Oil Point, California

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Title: Geology--Offshore of Coal Oil Point, California
Abstract:
This part of SIM 3302 presents data for the geologic and geomorphic map (see sheet 10, SIM 3302) of the Offshore of Coal Oil Point map area, California. The vector data file is included in "Geology_OffshoreCoalOilPoint.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshoreCoalOilPoint/data_catalog_OffshoreCoalOilPoint.html. The offshore part of the Offshore of Coal Oil Point map area largely consists of a gently offshore-dipping (less than 1 degree) shelf underlain by sediments derived primarily from relatively small coastal watersheds that drain the Santa Ynez Mountains. Shelf deposits are primarily sand (Qms) at depths less than about 35 to 50 m, and they are finer grained sediment such as very fine sand, silt, and clay (Qmsf) from depths of 35 to 50 m southward to the shelf break at a depth of about 90 m. The boundary between units Qms and Qmsf is based on observations and extrapolation from sediment sampling (see, for example, Reid and others, 2006) and camera ground-truth surveying. It is important to note that the boundary between units Qms and Qmsf should be considered transitional and approximate and is expected to shift as a result of seasonal- to annual- to decadal-scale cycles in wave climate, sediment supply, and sediment transport. Fine-grained deposits that are similar to unit Qmsf also are mapped at water depths greater than 90 m, below the shelf break on the upper slope; however, here they are identified as a separate unit (unit Qmsl) because of their location below the distinct shelf-slope geomorphologic break. Coarser grained, marine deposits (coarse sand to boulders) of units Qmsc, Qmscl, and Qsc are recognized on the basis of their high acoustic backscatter, their ground-truth-survey imagery, and, in some cases, their moderate seafloor relief. This coarse-grained facies is linked either to the mouths of steep coastal watersheds or to adjacent seafloor bedrock outcrops, and the deposits generally represent wave-winnowed lags of deltaic sediment. Two distinct lobes of coarse-grained sediment (unit Qmscl), present in deeper water (about 50 m) near the west edge of the map area, may similarly represent winnowed deltaic deposits that formed at lower sea levels during the latest Pleistocene or early Holocene. An isolated patch of clast-supported cobbles (unit Qsc), which rests on bedrock south of Coal Oil Point at a water depth of 70 m, also may have been deposited at lower sea levels during the late Pleistocene. Offshore bedrock exposures are mapped as either the Miocene Monterey Formation (Tm, Tmu, Tmm), the late Miocene and early Pliocene Sisquoc Formation (Tsq), or the undivided Quaternary and Tertiary bedrock (QTbu) or undivided Tertiary bedrock (Tbu) units on the basis of the confidence in extending the onshore mapping of Minor and others (2009) offshore. Midshelf to outer shelf bedrock exposures are all mapped as undivided units; however, offshore sampling data (see, for example, Kunitomi and others, 1998), as well as regional cross sections that are constrained by petroleum exploration data and sampling (Redin, 2005; Redin and others, 2005), have suggested that these seafloor outcrops predominantly are late Miocene and Pliocene strata. These rocks have been uplifted in a large, regional, internally warped, south-dipping homocline that formed above the blind, north-dipping Pitas Point-North Channel Fault system; the fault tip is inferred to lie beneath the continental slope, about 6 to 7 km offshore. Bedrock is, in some places, overlain by a thin (less than 1 m?) veneer of sediment, recognized on the basis of high backscatter, flat relief, continuity with moderate- to high-relief bedrock outcrops, and (in some cases) high-resolution seismic-reflection data; these areas, which are mapped as composite units Qms/Tu, Qms/Tsq, Qms/Tmu, Qms/Tmm, Qms/Tm, Qms/Tbu, or Qmsf/QTbu, are interpreted as ephemeral sediment layers that may or may not be continuously present, whose presence or absence is a function of the recency and intensity of storm events, seasonal and (or) annual patterns of sediment movement, or longer term climate cycles. The Offshore of Coal Oil Point map area includes the upper part of the large (130 km2), well-documented submarine Goleta landslide complex (Eichhubl and others, 2002; Fisher and others, 2005; Greene and others, 2006). Greene and others (2006) reported that the complex, which measures 14.6 km long and 10.5 km wide and extends from water depths of 90 to 574 m, has displaced about 1.75 km3 of landslide debris during the Holocene; they described it as a compound, multiphase submarine landslide that contains both surficial slump blocks and mud flows, in three distinct segments (west, central, and east lobes). Each segment consists of a distinct headwall scarp (units Qglwh, Qglch, Qgleh), a downdropped head block (units Qglwb, Qglcb, Qgleb), and several composite slide-debris lobes (units Qglw5, Qfglw4, Qglw3, Qglw2, Qglw1, Qglc4, Qglc3, Qglc2a, Qglc2, Qfle5, Qgle4, Qgle3, Qgle2). The geologic map geomorphic map on sheet 10 (SIM 3302) shows the upper approximately 3 km of this landslide complex; in addition, the seismic-reflection profile SB-145 (fig. 3 on sheet 8, SIM 3302), which crosses the east lobe of the landslide complex, illustrates its subsurface characteristics. The landslide source is inferred to be Pleistocene-age, shelf-edge deltaic sediments deposited during Quaternary sea-level lowstands, and Fisher and others (2005) suggested that the youngest landslides formed about 8,000 to 10,000 years ago. The Santa Barbara Channel region, including the map area, has a long history of petroleum production (Barnum, 1998) that began in 1928 with discovery of the Ellwood oil field. Subsequent discoveries in the offshore part of the map area include the South Ellwood offshore oil field, the Coal Oil Point oil field, and the Naples oil and gas field (Brickey, 1998; Galloway, 1998). Oil and gas are mainly sourced by the Miocene Monterey Formation; the reservoirs are in the Vaqueros Formation, the Rincon Shale, and the Monterey Formation. Development of the South Ellwood offshore oil field began in 1966 from platform "Holly," which was the last platform to be installed in California's State Waters. Debris and infrastructure associated with platform "Holly," as well as with seep containment devices ("seep tents"), are mapped as unit pd. Hornafius and others (1999) described "the world's most spectacular marine hydrocarbon seeps" in the Coal Oil Point map area, and these seeps release an estimated 36 metric tons of methane and 17 metric tons reactive organic gas (ethane, propane, butane, and higher hydrocarbons) per day. Areas of grouped to solitary pockmarks (unit Qmp) caused by gas seeps are common features. In addition, numerous asphalt (tar) deposits (unit Qas) associated with hydrocarbon seeps and gas vents are mapped both onshore and offshore. The offshore deposits, which have been confirmed with seafloor video observations, often are localized along bedrock structures such as faults or the crests of anticlines, forming bathymetric features that are morphologically similar to bedrock outcrops but are distinguished from them on the basis of their low acoustic backscatter. Although many such asphalt deposits are too small to be shown on the map, the larger deposits can cover as much as several hundred square meters. References Cited: Barnum, H.P., 1998, Redevelopment of the western portion of the Rincon offshore oil field, Ventura, California, in Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., eds., Structure and petroleum geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, Pacific Section, and Coast Geological Society, Miscellaneous Publication 46, p. 201-215. Brickey, M.R., 1998, Oil and gas fields of the Santa Barbara Channel area, in Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., eds., Structure and petroleum geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, Pacific Section, and Coast Geological Society, Miscellaneous Publication 46, preface (2 p.). Eichhubl, P., Greene, H.G., and Maher, N., 2002, Physiography of an active transpressive margin basin--High-resolution bathymetry of the Santa Barbara basin, southern California continental borderland: Marine Geology, v. 184, p. 95-120. Fisher, M.A., Normark, W.R., Greene, H.G., Lee, H.J., and Sliter, R.W., 2005, Geology and tsunamigenic potential of submarine landslides in Santa Barbara Channel, southern California: Marine Geology, v. 224, p. 1-22. Galloway, J., 1998, Chronology of petroleum exploration and development in the Santa Barbara Channel area, offshore southern California, in Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., eds., Structure and petroleum geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, Pacific Section, and Coast Geological Society, Miscellaneous Publication 46, p. 1-12, 1 sheet. Greene, H.G., Murai, L.Y., Watts, P., Maher, N.A., Fisher, M.A., and Eichhubl, P., 2006, Submarine landslides in the Santa Barbara channel as potential tsunami sources: Natural Hazards and Earth System Sciences, v. 6, p. 63-88. Hornafius, J.S., Quigley, D.C., and Luyendyk, B.P., 1999, The world's most spectacular marine hydrocarbon seeps (Coal Oil Point, Santa Barbara Channel, California)--Quantification of emissions: Journal of Geophysical Research - Oceans, v. 104, p. 20,703-20,711. Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., eds., 1998, Structure and petroleum geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, Pacific Section, and Coast Geological Society, Miscellaneous Publication 46, 328 p. Minor, S.A., Kellogg, K.S., Stanley, R.G., Gurrola, L.D., Keller, E.A., and Brandt, T.R., 2009, Geologic map of the Santa Barbara coastal plain area, Santa Barbara County, California: U.S. Geological Survey Scientific Investigations Map 3001, scale 1:25,000, 1 sheet, pamphlet 38 p., available at http://pubs.usgs.gov/sim/3001. Redin, T., 2005, Santa Barbara Channel structure and correlation sections--Correlation Section no. 36, N-S structure and correlation section, western Santa Ynez Mountains across the Santa Barbara Channel to Santa Rosa Island: American Association of Petroleum Geologists, Pacific Section, Publication CS 36, 1 sheet. Redin, T., Kamerling, M., and Forman, J., 2005, Santa Barbara Channel structure and correlation sections--Correlation Section no. 35, North Ellwood-Coal Oil Point area across the Santa Barbara Channel to the north coast of Santa Cruz Island: American Association of Petroleum Geologists, Pacific Section, Publication CS 35, 1 sheet. Reid, J.A., Reid, J.M., Jenkins, C.J., Zimmerman, M., Williams, S.J., and Field, M.E., 2006, usSEABED--Pacific Coast (California, Oregon, Washington) offshore surficial-sediment data release: U.S. Geological Survey Data Series 182, available at http://pubs.usgs.gov/ds/2006/182/.
Supplemental_Information:
Map political location: Santa Barbara County, California Compilation scale: 1:24,000 Base maps used are hillshades generated from IfSAR, LiDAR, and multibeam mapping both onshore and offshore (see sheet 2, SIM 3302, for more information).
  1. How might this data set be cited?
    Conrad, J.E., Ritchie, A.C., Johnson, S.Y., Greene, H.G., and Dartnell, P., 2014, Geology--Offshore of Coal Oil Point, California:.

    This is part of the following larger work.

    Johnson, Samuel Y., Dartnell, Peter, Cochrane, Guy R., Golden, Nadine E., Phillips, Eleyne L., Ritchie, Andrew C., Kvitek, Rikk G., Dieter, Bryan E., Conrad, James E., Lorenson, Thomas D., Krigsman, Lisa M., Greene, H. Gary, Endris, Charles A., Seitz, Gordon G., Finlayson, David P., Sliter, Ray W., Wong, Florence L., Erdey, Mercedes D., Gutierrez, Carlos I., Leifer, Ira, Yoklavich, Mary M., Draut, Amy E., Hart, Patrick E., Hostettler, Frances D., Peters, Kenneth E., Kvenvolden, Keith A, Rosenbauer, Robert J., Fong, Grace, and Cochran, Susan A., 2014, California State Waters Map Series--Offshore of Coal Oil Point, California: Scientific Investigations Map SIM 3302, U.S. Geological Survey, Reston, VA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -120.007
    East_Bounding_Coordinate: -119.807
    North_Bounding_Coordinate: 34.4973
    South_Bounding_Coordinate: 34.3408
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2014
    Currentness_Reference:
    Publication Date
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: vector digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Vector data set. It contains the following vector data types (SDTS terminology):
      • GT-polygon composed of chains (257)
    2. What coordinate system is used to represent geographic features?
      The map projection used is WGS 1984 UTM Zone 11N.
      Projection parameters:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -117.0
      Latitude_of_Projection_Origin: 0.0
      False_Easting: 500000.0
      False_Northing: 0.0
      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.0001
      Ordinates (y-coordinates) are specified to the nearest 0.0001
      Planar coordinates are specified in Meter
      The horizontal datum used is D WGS 1984.
      The ellipsoid used is WGS 1984.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257223563.
  7. How does the data set describe geographic features?
    MapUnitPolys
    Polygons representing geologic / geomorphic map units (Source: This report)
    OBJECTID
    Internal feature number. (Source: ESRI) Sequential unique whole numbers that are automatically generated.
    Shape
    Feature geometry. (Source: ESRI) Coordinates defining the features.
    MapUnitAbbrev
    Map Unit abbreviation (Source: This report)
    ValueDefinition
    pdOil-platform debris
    QasAsphalt deposits
    Qas?Asphalt deposits, questionable
    QmsMarine nearshore and shelf deposits
    QmscCoarse-grained marine nearshore and shelf deposits
    QmsclMarine shelf-sediment lobes
    Qmscl?Marine shelf-sediment lobes, questionable
    QmsfFine-grained marine shelf deposits
    QmpMarine pockmarks
    QmslMarine upper slope deposits
    QscMarine or nonmarine coarse-grained deposits
    Qmsf/QTbuFine-grained-sediment-covered undivided Pleistocene, Pliocene, and Miocene bedrock
    Qms/TbuSediment-covered undivided Pliocene and Miocene bedrock
    Qms/TmSediment-covered undivided Monterey Formation
    Qms/TmmSediment-covered Monterey Formation, middle shale unit
    Qms/TmuSediment-covered Monterey Formation, upper siliceous unit
    Qms/TsqSediment-covered Sisquoc Formation
    Qms/TuSediment-covered unnamed mudstone
    QTbuUndivided Pleistocene, Pliocene, and Miocene bedrock
    TsqSisquoc Formation
    Tsq?Sisquoc Formation, questionable
    TmMonterey Formation, undivided
    TmmMonterey Formation, middle shale unit
    TbuTertiary bedrock, undivided
    TrRincon Shale
    QglwhGoleta landslide headwall, west lobe
    QglwbGoleta landslide head block, west lobe
    Qglw5Goleta landslide fifth-phase flow deposit, west lobe
    Qglw4Goleta landslide fourth-phase flow deposit, west lobe
    Qglw3Goleta landslide third-phase flow deposit, west lobe
    Qglw2Goleta landslide second-phase flow deposit, west lobe
    Qglw1Goleta landslide first-phase flow deposit, west lobe
    QglchGoleta landslide headwall, central lobe
    QglcbGoleta landslide head block, central lobe
    Qglc4Goleta landslide fourth-phase flow deposit, central lobe
    Qglc3Goleta landslide third-phase flow deposit, central lobe
    Qglc2aGoleta landslide, secondary failure of second-phase flow deposit, central lobe
    Qglc2Goleta landslide second-phase flow deposit, central lobe
    QglehGoleta landslide headwall, east lobe
    QglebGoleta landslide head block, east lobe
    Qgle5Goleta landslide fifth-phase flow deposit, east lobe
    Qgle4Goleta landslide fourth-phase flow deposit, east lobe
    Qgle3Goleta landslide third-phase flow deposit, east lobe
    Qgle2Goleta landslide second-phase flow deposit, east lobe
    MapUnit
    short description of map unit (Source: This report) text description of map unit
    Shape_Length
    Length of feature in internal units. (Source: ESRI) Positive real numbers that are automatically generated.
    Shape_Area
    Area of feature in internal units squared. (Source: ESRI) Positive real numbers that are automatically generated.
    RuleID
    Representation rule identifier (Source: This report) This field contains the representation rule in the ArcGIS file geodatabase which applies a solid color fill of a specified CMYK value to each polygon. Representation rules have the same name as the map unit abbreviation.

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • J.E. Conrad
    • A.C. Ritchie
    • S.Y. Johnson
    • H.G. Greene
    • P. Dartnell
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    USGS Pacific Coastal & Marine Science Center
    Attn: Stephen Hartwell
    Geologist
    400 Natural Bridges Drive
    Santa Cruz, CA
    USA

    (831) 460-7814 (voice)
    (831) 427-4748 (FAX)
    shartwell@usgs.gov

Why was the data set created?

To expand geologic mapping to the seafloor within California's State Waters, to update coastal geologic mapping, and to contribute to a uniform regional geologic database. Additionally, to provide a geologic map for the public and geoscience community to aid in assessments and mitigation of geologic hazards in the Santa Barbara coastal plain region and to provide sufficient geologic information for land-use and land-management decisions both onshore and offshore.

How was the data set created?

  1. From what previous works were the data drawn?
    SIM 3302 (sheet 1) (source 1 of 3)
    Dartnell, Peter, Phillips, Eleyne, Finlayson, David, Conrad, James, and Kvitek, Rikk, 2014, Bathymetry--Offshore of Coal Oil Point, California: Scientific Investigations Map SIM 3302 (sheet 1), U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    See metadata ("Bathymetry_OffshoreCoalOilPoint_metadata.txt") in SIM 3302 for source data and postprocessing/reprocessing information.
    Type_of_Source_Media: digital file of gridded bathymetry data (ArcInfo GRID)
    Source_Contribution: Gridded bathymetry data (2-meter resolution).
    SIM 3302 (sheet 3) (source 2 of 3)
    Dartnell, Peter, Phillips, Eleyne, Finlayson, David, Conrad, James, and Kvitek, Rikk, 2014, Acoustic Backscatter A--Offshore of Coal Oil Point, California: Scientific Investigations Map SIM 3302 (sheet 3), U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    See metadata for backscatter data ("BackscatterA_CSUMB_OffshoreCoalOilPoint_metadata.txt," "BackscatterB_USGS_OffshoreCoalOilPoint_metadata.txt," and "BackscatterC_Fugro_OffshoreCoalOilPoint_metadata.txt") in SIM 3302 for amplitude source data and postprocessing/reprocessing information.
    Type_of_Source_Media: digital file of gridded amplitude data (ArcInfo GRID)
    Source_Contribution: Gridded amplitude data (2-meter resolution).
    Sliter and others (2008) (source 3 of 3)
    Ray W. Sliter, Peter J. Triezenberg, Patrick E. Hart, Amy E. Draut, William R. Normark, and James E. Conrad, 2008, High-resolution chirp and mini-sparker seismic-reflection data from the southern California continental shelf--Gaviota to Mugu Canyon: U.S. Geological Survey Open-File Report 2008-1246, U.S. Geological Survey, Reston, VA.

    Online Links:

    Type_of_Source_Media:
    seismic data files (.sgy files) ASCII lat/long shotpoint files TIFF images of processed seismic lines
    Source_Contribution:
    Digital seismic data used to interpret subsurface geologic structure
  2. How were the data generated, processed, and modified?
    Date: 2010 (process 1 of 7)
    Map unit polygons were digitized over underlying 2-meter base layers developed from multibeam bathymetry and backscatter data. Derivatives such as slope and curvature were generated from source rasters. Interpreted rasters include amplitude, hillshaded bathymetry (using various illumination angles and vertical exaggeration), slope, and curvature. Curvature was decomposed into profile and plan curvature for analysis purposes.
    Date: 2011 (process 2 of 7)
    The mapped area was extended to the shoreline by generating a DEM using U.S. Army Corps of Engineers (USACE) National Coastal Mapping Program's lidar data collected in 2009 (U.S. Army Corps of Engineers, unpub. data). These elevation data were then used to generate a shoreline at the NAVD88 +1.33 m contour, defined as the operational MHW shoreline by Weber and others (2005). The resulting boundary was transformed to WGS 84 UTM Zone 11 North in ArcGIS 10 using the NAD83 to WGS84 (ITRF00) transformation algorithm. This boundary was then used to extend and trim both onshore and offshore geology in the print and PDF product. The transformed boundary is contained within the WGS84 "contacts" feature class and identified as a shoreline in the associated representation rules. Only data for offshore map units are released digitally in this publication. For onshore geology (sheet 10, SIM 3302), see Dibblee (1981, 1987a,b) and Minor and others (2009). References Cited: Barnard, P.L., and Hoover, D., 2010, A seamless, high-resolution coastal digital elevation model (DEM) for southern California: U.S. Geological Survey Data Series 487, 8 p., available at http://pubs.usgs.gov/ds/487/. Dibblee, T.W., Jr., 1981, Geologic map of the Tajiguas quadrangle, California: U.S. Geological Survey Open-File Report 81?371, 1:24,000. Dibblee, T.W., Jr., 1987a, Geologic map of the Dos Pueblos quadrangle, Santa Barbara County, California: Santa Barbara, Calif., Dibblee Geological Foundation Map DF?09, scale 1:24,000. Dibblee, T.W., Jr., 1987b, Geologic map of the Goleta quadrangle, Santa Barbara County, California: Santa Barbara, Calif., Dibblee Geological Foundation Map DF?07, scale 1:24,000. Minor, S.A., Kellogg, K.S., Stanley, R.G., Gurrola, L.D., Keller, E.A., and Brandt, T.R., 2009, Geologic map of the Santa Barbara coastal plain area, Santa Barbara County, California: U.S. Geological Survey Scientific Investigations Map 3001, scale 1:25,000, 1 sheet, pamphlet 38 p., available at http://pubs.usgs.gov/sim/3001/. Weber, K.M., List, J.H., and Morgan, K.L., 2005, An operational Mean High Water datum for determination of shoreline position from topographic lidar data: U.S. Geological Survey Open-File Report 2005-1027 available at http://pubs.usgs.gov/of/2005/1027/.
    Date: 05-Oct-2017 (process 3 of 7)
    Added Distribution_Information section to metadata to facilitate data download. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Alan O. Allwardt
    Contractor -- Information Specialist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7551 (voice)
    831-427-4748 (FAX)
    aallwardt@usgs.gov
    Date: 05-Oct-2017 (process 4 of 7)
    Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Alan O. Allwardt
    Contractor -- Information Specialist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7551 (voice)
    831-427-4748 (FAX)
    aallwardt@usgs.gov
    Date: 26-Apr-2018 (process 5 of 7)
    Added keywords from Coastal and Marine Ecological Classification Standard (CMECS) to metadata. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Alan O. Allwardt
    Contractor -- Information Specialist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7551 (voice)
    831-427-4748 (FAX)
    aallwardt@usgs.gov
    Date: 19-Oct-2020 (process 6 of 7)
    Edited metadata to add keywords section with USGS persistent identifier as theme keyword. No data were changed. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 14-Oct-2021 (process 7 of 7)
    Performed minor edits to the metadata to correct typos. No data were changed Person who carried out this activity:
    U.S. Geological Survey
    Attn: Susan A. Cochran
    Geologist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7545 (voice)
    scochran@usgs.gov
  3. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
    Polygons were primarily mapped by one of the following methods: (1) interpretation of 2-meter-resolution hillshaded bathymetry data from bathymetric lidar and sonar surveys (see sheets 1 and 2, SIM 3302); (2) interpretation of 2-meter-resolution amplitude (backscatter) data from bathymetric sonar surveys (see sheet 3, SIM 3302); (3) interpretation of 2-meter slope and curvature derivatives of bathymetry data and (4) interpretation of seismic-reflection-profile data (see sheet 8, SIM 3302). Map Unit contact locations were interpreted typically at a scale of between 1:1,000 and 1:2,000 using the above base data. Bathymetric sonar and LiDAR data have a horizontal accuracy greater than the resolution of the base data. Map unit contacts were digitized by heads-up screen digitization of line data on 2-meter-resolution DEMs described above. Horizontal accuracy is estimated to be between 2 and 5 meters depending on how clearly contacts can be resolved. Most digitized positions on the map are estimated to have better than 5 m horizontal accuracy. There is no elevation data in the database.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    Data are complete: no offshore features that could be accurately identified and represented at the compilation scale of 1:24,000 were eliminated or generalized. The smallest area represented is approximately 100 square meters. All geospatial database elements are attributed.
  5. How consistent are the relationships among the observations, including topology?
    Map elements were visually checked for overshoots, undershoots, duplicate features, polygon closure, and other errors by the lead authors and by the GIS technician(s) who created the digital database. Review drafts of the map were reviewed internally by at least two other geologists for consistency with basic geologic principles and general conformity to USGS mapping standards.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints:
If physical samples or materials are available, constraints on their on-site access are described in "WR CMG Sample Distribution Policy" at URL: http://walrus.wr.usgs.gov/infobank/programs/html/main/sample-dist-policy.html
Use_Constraints:
This information is not intended for navigational purposes. Read and fully comprehend the metadata prior to data use. Uses of these data should not violate the spatial resolution of the data. Where these data are used in combination with other data of different resolution, the resolution of the combined output will be limited by the lowest resolution of all the data. Acknowledge the U.S. Geological Survey in products derived from these data. Share data products developed using these data with the U.S. Geological Survey. This database has been approved for release and publication by the Director of the USGS. Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use. Although this Federal Geographic Data Committee-compliant metadata file is intended to document these data in nonproprietary form, as well as in ArcInfo format, this metadata file may include some ArcInfo-specific terminology.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey
    345 Middlefield Rd
    Menlo Park, CA
    USA

    (650) 329-4309 (voice)
  2. What's the catalog number I need to order this data set?
  3. What legal disclaimers am I supposed to read?
    Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 14-Oct-2021
Metadata author:
U.S. Geological Survey, Coastal and Marine Geology Program
Attn: Stephen R. Hartwell
400 Natural Bridges Drive
Santa Cruz, CA
US

831-460-7814 (voice)
831-427-4748 (FAX)
shartwell@usgs.gov
Metadata standard:
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