Sediment Thickness--Salt Point to Drakes Bay, California

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Frequently anticipated questions:

What does this data set describe?

Title: Sediment Thickness--Salt Point to Drakes Bay, California
Abstract:
This part of DS 781 presents data for the sediment-thickness map of the Salt Point to Drakes Bay, California, region. The raster data file is included in "SedimentThickness_SaltPointToDrakesBay.zip," which is accessible from https://pubs.usgs.gov/ds/781/SaltPointToDrakesBay/data_catalog_SaltPointToDrakesBay.html.
As part of the USGS's California State Waters Mapping Project, a 20-m grid of sediment thickness for the seafloor within the 3-nautical mile limit between Salt Point and Drakes Bay was generated from seismic-reflection data collected in 2009 supplemented with outcrop and geologic structure from DS 781. The resulting grid covers an area of approximately 717 sq km. The volume of sediment accumulated since the Last Glacial Maximum is approximately 6,800 million cubic meters. Contours at 2.5-meter intervals were derived from this grid.
Supplemental_Information:
Additional information about the USGS field activity from which some of these data were derived is available online at:
https://cmgds.marine.usgs.gov/fan_info.php?fan=S809SC
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 Esri format, this metadata file may include some Esri-specific terminology.
  1. How might this data set be cited?
    Johnson, Samuel Y., Hartwell, Stephen R., Watt, Janet T., and Sliter, Ray W., 2014, Sediment Thickness--Salt Point to Drakes Bay, California: Data Series DS 781, U.S. Geological Survey, Reston, VA.

    Online Links:

    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?
    https://pubs.usgs.gov/ds/781/SaltPointToDrakesBay/images/SedimentThickness_SaltPointToDrakesBay.jpg (JPEG)
    Map of sediment thickness contours in the Salt Point to Drakes Bay region of California
  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: raster digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Raster data set. It contains the following raster data types:
      • Dimensions 4276 x 3095 x 1, type Grid Cell
    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 20.000000
      Ordinates (y-coordinates) are specified to the nearest 20.000000
      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?
    Entity_and_Attribute_Overview:
    Grid value is thickness of sediment above the transgressive surface of the last glacial maximum in meters.
    Entity_and_Attribute_Detail_Citation: U.S. Geological Survey

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: 05-Oct-2017 (process 5 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 6 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 7 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
    Date: 24-Mar-2023 (process 8 of 8)
    Information about the data available for download and different Network Resource Name links and details were given in the Standard Order Process section. Minor typos were corrected. No data information was 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:
    Susan A Cochran
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    Geologist
    2885 Mission Street
    Santa Cruz, CA
    USA

    (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 None
Use_Constraints USGS-authored or produced data and information are in the public domain from the U.S. Government and are freely redistributable with proper metadata and source attribution. Please recognize and acknowledge the U.S. Geological Survey and California State University, Monterey Bay, Seafloor Mapping Lab (CSUMB) as the originator(s) of the dataset and in products derived from these data. This information is not intended for navigation purposes.
  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? The .zip file (https://pubs.usgs.gov/ds/781/SaltPointToDrakesBay/data/SedimentThickness_SaltPointToDrakesBay.zip) includes the .lyr, .tfw, .tif, .tif.aux.xml, and .tif.ovr files, as well as FGDC-compliant metadata for the Sediment Thickness data layer in the Salt Point to Drakes Bay region of California.
  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: 24-Mar-2023
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/SedimentThickness_SaltPointToDrakesBay_metadata.faq.html>
Generated by mp version 2.9.51 on Mon Apr 10 10:34:50 2023