Isopachs--Salt Point to Drakes Bay, California

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What does this data set describe?

Title: Isopachs--Salt Point to Drakes Bay, California
Abstract:
This part of DS 781 presents data for the isopachs for the Salt Point to Drakes Bay, California, region. The vector data file is included in "Isopachs_SaltPointToDrakesBay.zip," which is accessible from http://pubs.usgs.gov/ds/781/SaltPointToDrakesBay/data_catalog_SaltPointToDrakesBay.html.
As part of the USGS's California Seafloor Mapping Program, a 20-m grid ofsediment thickness for the seafloor within the 3-nautical-mile limit of California's State Waters between Salt Point and Drakes Bay was generated from seismic-reflection data collected in 2009 (USGS activity (S-8-09-NC) supplemented with outcrop and geologic structure from sheet DS 781. The resulting grid covers an area of approximately 600 sq km. The volume of sediment accumulated since the Last Glacial Maximum is approximately 9,000 million cubic meters. Contours at 2.5-meter intervals were derived from this grid.
Supplemental_Information:
Sediment thickness and volume within each of the map areas
 Salt Point    38.639622 38.479620 -123.482704 -123.278809
 Fort Ross     38.556494 38.396794 -123.305678 -123.102404
 Bodega Bay    38.411542 38.252067 -123.172536 -122.969899
 Tomales Point 38.255180 38.095716 -123.097226 -122.895023
 Point Reyes   38.098263 37.938810 -123.094511 -122.892742
 Drakes Bay    38.038192 37.878737 -122.966411 -122.764735

   -----sediment thickness--------
                  Area            Volume
  Map block      (sq km)  Mean  (million cu m)
  Salt Point      117     12.5      1464
  Fort Ross       100     21.5      2157
  Bodega Bay      128      8.5      1084
  Tomales Point   108      2.1       230
  Point Reyes     175      7.9      1387
  Drakes Bay       89      5.3       476
Additional information about the field activities from which this data set was derived are available online at
 http://walrus.wr.usgs.gov/infobank/s/s809nc/html/s-8-09-nc.meta.html
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Although this Federal Geographic Data Committee-compliant metadata file is intended to document the data set in nonproprietary form, as well as in ArcInfo format, this metadata file may include some ArcInfo-specific terminology.
  1. How might this data set be cited?
    Johnson, Samuel Y., Hartwell, Stephen R., Watt, Janet T., and Sliter, Ray W., 2014, Isopachs--Salt Point to Drakes Bay, California:.

    This is part of the following larger work.

    Golden, Nadine E., 2013, California State Waters Map Series Data Catalog: Data Series DS 781, U.S. Geological Survey, Reston, VA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -123.473993
    East_Bounding_Coordinate: -122.762732
    North_Bounding_Coordinate: 38.640196
    South_Bounding_Coordinate: 37.868433
  3. What does it look like?
    http://pubs.usgs.gov/ds/781/SaltPointToDrakesBay/images/Isopachs_SaltPointToDrakesBay.jpg (JPEG)
    map of sediment thickness contours
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2009
    Currentness_Reference:
    ground condition
  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):
      • String (1147)
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 10
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -117.000000
      Latitude_of_Projection_Origin: 0.000000
      False_Easting: 500000.000000
      False_Northing: 0.000000
      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 50.000000
      Ordinates (y-coordinates) are specified to the nearest 50.000000
      Planar coordinates are specified in meters
      The horizontal datum used is D_WGS_1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257224.
  7. How does the data set describe geographic features?
    isopachs
    lines of equal thickness (Source: standard sedimentology)
    FID
    Internal feature number. (Source: ESRI) Sequential unique whole numbers that are automatically generated.
    Shape
    Feature geometry. (Source: ESRI) Coordinates defining the features.
    ID
    sequential feature number (Source: this study) sequential feature numbers
    CONTOUR
    line of equal thickness (Source: this study) thickness measure
    Type
    Type of contour (Source: This report)
    ValueDefinition
    IndexContour at 10m interval
    IntermediateContours at 2.5m interval

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Samuel Y. Johnson
    • Stephen R. Hartwell
    • Janet T. Watt
    • Ray W. Sliter
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    Attn: PCMSC Science Data Coordinator
    2885 Mission Street
    Santa Cruz, CA
    US

    831-427-4747 (voice)
    pcmsc_data@usgs.gov

Why was the data set created?

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.

How was the data set created?

  1. From what previous works were the data drawn?
    S-8-09-NC (source 1 of 1)
    U.S. Geological Survey (USGS) , Coastal and Marine Geology Program (CMGP), 2013, Seismic-reflection data acquisition data of field activity S-8-09-NC Stinson Beach to point Arena 09/08/2009 to 09/30/2009: U.S. Geological Survey (USGS) , Coastal and Marine Geology (CMG), Menlo Park, CA.

    Online Links:

    Type_of_Source_Media: ASCII lat/long shot point files
    Source_Contribution:
    Digital seismic data used to interpret subsurface geologic structure
  2. How were the data generated, processed, and modified?
    Date: 2013 (process 1 of 8)
    Chirp and sparker seismic-reflection data from USGS field activity S-8-09-NC were imported to SEISWORKS.
    Date: 2013 (process 2 of 8)
    Seabed and depth to Last Glacial Maximum horizons digitized in Seisworks.
    Date: 2013 (process 3 of 8)
    Data exported and converted with 1500m/sec velocity in water and 1600 m/sec velocity in sediment.
    Date: 2013 (process 4 of 8)
    X, Y locations and sediment thickness value Z imported to ArcGIS format as points, interpolated to preliminary surface with TopoRaster. Supplemental manually generated contours were combined for secondary calculation.
    Date: 2013 (process 5 of 8)
    Sediment thickness grid contoured at 2.5-meter intervals.
    Date: 05-Oct-2017 (process 6 of 8)
    Modified Distribution_Information section in 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: 19-Oct-2020 (process 7 of 8)
    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: 21-Oct-2021 (process 8 of 8)
    Edited metadata to add USGS Thesaurus keywords and perform minor edits to bring the metadata up to current PCMSC standards. No data were changed. The metadata available from a harvester may supersede metadata bundled within a download file. Users are advised to compare the metadata dates to determine which metadata file is most recent. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Susan 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?
    Data points are approximately 1 m apart along tracklines and 1000-2000 m apart between tracks. 50-m cell size for interpolation is better supported along track than between.
  2. How accurate are the geographic locations?
    The chirp sonar instrument is deployed under the research vessel with about 10m of variation in position. The sparker position may vary as much as 20m from the navigation reference on the vessel.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    Sediment thickness data points exported from Seisworks profiling software were processed within the California 3-nmi limit.
  5. How consistent are the relationships among the observations, including topology?
    All vector geometry and attributes present.

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: 21-Oct-2021
Metadata author:
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Attn: PCMSC Science Data Coordinator
2885 Mission Street
Santa Cruz, CA
US

831-427-4747 (voice)
pcmsc_data@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/pcmsc/SeriesReports/DS_DDS/DS_781/SaltPointToDrakesBay/Isopachs_SaltPointToDrakesBay_metadata.faq.html>
Generated by mp version 2.9.50 on Thu Nov 18 14:01:14 2021