Processed, high-resolution, chirp seismic-reflection data collected in San Pablo Bay (northern California) during field activity 2014-639-FA from 10/06/2014 to 10/10/2014

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Frequently anticipated questions:


What does this data set describe?

Title:
Processed, high-resolution, chirp seismic-reflection data collected in San Pablo Bay (northern California) during field activity 2014-639-FA from 10/06/2014 to 10/10/2014
Abstract:
This dataset includes processed, high-resolution chirp seismic-reflection data collected in 2014 by the U.S. Geological Survey (USGS) in San Pablo Bay, northern California.
Supplemental_Information:
Additional information about the field activity from which these data were derived is available online at http://cmgds.marine.usgs.gov/fan_info.php?fan=2014-639-FA. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
  1. How might this data set be cited?
    Watt, Janet T., Hart, Patrick E., and Kluesner, Jared W., 2016, Processed, high-resolution, chirp seismic-reflection data collected in San Pablo Bay (northern California) during field activity 2014-639-FA from 10/06/2014 to 10/10/2014: data release DOI:10.5066/F74T6GF1, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

    Online Links:

    This is part of the following larger work.

    Watt, Janet T., Hart, Patrick E., and Kluesner, Jared W., 2016, Chirp seismic-reflection data: San Pablo Bay, California: data release DOI:10.5066/F74T6GF1, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -122.47772
    East_Bounding_Coordinate: -122.27734
    North_Bounding_Coordinate: 38.13287
    South_Bounding_Coordinate: 37.98376
  3. What does it look like?
    https://www.sciencebase.gov/catalog/item/imap/57322151e4b0dae0d5dc1efa (Web service)
    Trackline map of 2014-639-FA
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 06-Oct-2014
    Ending_Date: 10-Oct-2014
    Currentness_Reference:
    ground condition at the time the data were collected
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: chirp seismic-reflection data in SEG-Y format
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      Indirect_Spatial_Reference:
      Horizontal X and Y locations for the seismic profile locations are provided in ASCII position files and are stored in the SEG-Y data trace headers in the standard header locations.
      This is a Point data set. It contains the following vector data types (SDTS terminology):
      • Point
    2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 1.0E-5. Longitudes are given to the nearest 1.0E-5. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257.
      Vertical_Coordinate_System_Definition:
      Depth_System_Definition:
      Depth_Datum_Name: Local surface
      Depth_Resolution: 0.1
      Depth_Distance_Units: meters
      Depth_Encoding_Method: Attribute values
  7. How does the data set describe geographic features?
    Entity_and_Attribute_Overview:
    Navigation and Seismic Shots with Time Stamp in standard SEG-Y file format
    Entity_and_Attribute_Detail_Citation:
    Society of Exploration Geophysicists (SEG) Technical Standards, available for download at http://seg.org/Publications/SEG-Technical-Standards

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Janet T. Watt
    • Patrick E. Hart
    • Jared W. Kluesner
  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 were collected as part of USGS efforts to better understand the fault geometry of the Hayward and Rodgers Creek faults beneath the bay. These data and information are intended for science researchers, students from elementary through college, policy makers, and general public.

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
    Date: 2016 (process 1 of 5)
    Seismic-reflection SEG-Y files were sub-sampled at twice the sample interval, using Echos software, to make swell correction more effective. Results were exported as a new SEG-Y file.
    Date: 2016 (process 2 of 5)
    Selected SEG-Y files were displayed using Kingdom Suite software and the water bottom was picked along each profile where seafloor relief was minimal. Swell corrections were calculated based on the water bottom horizon, and applied to the sub-sampled SEG-Y files using Sioseis software (see: http://sioseis.ucsd.edu/procs.html). Results were exported as a new SEG-Y. Note, if the sea state was flat, no swell correction was applied (lines: 2,3,5,8,9,14), and portions of some profiles were NOT swell-filtered b/c of seafloor relief. Where there is seafloor relief (i.e. ripples, sandwaves), if you were to apply a swell correction, you would introduce inaccurate shifts to the subsurface reflectors that were NOT the result of only sea-surface swell.
    Date: 2016 (process 3 of 5)
    Predictive deconvolution was applied using Sioseis software to the swell-corrected SEG-Y files, using the whole trace with a 0.2 ms gap. A 15-trace mix was applied and the results were exported as a new SEG-Y file. Person who carried out this activity:
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    Attn: Janet T. Watt
    Geologist
    2885 Mission Street
    Santa Cruz, CA
    US

    831-460-7565 (voice)
    831-427-4748 (FAX)
    jwatt@usgs.gov
    Date: Nov-2025 (process 4 of 5)
    Online_Linkage and Network_Resources URLs were corrected. In addition, edits were made as needed to bring the metadata up to current PCMSC standards including standardizing doi# links, and correcting typos. Point of Contact and Metadata Contact information sections were changed to static PCMSC contact information. No data were changed. Users are advised to compare the metadata date of this file to any similar file to ensure they are using the most recent version. Person who carried out this activity:
    Susan A Cochran
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    2885 Mission St.
    Santa Cruz, CA
    United States

    831-460-7545 (voice)
    scochran@usgs.gov
    Date: 19-Oct-2020 (process 5 of 5)
    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
  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?
    Identified as best available version.
  2. How accurate are the geographic locations?
    Unspecified
  3. How accurate are the heights or depths?
    Unspecified
  4. Where are the gaps in the data? What is missing?
    Dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details. Due to attenuation of the chirp signal by bay muds and persistent natural gas layers in San Pablo Bay sediments, we were only able to image the upper 2 to 5 meters of the sub-seafloor.
  5. How consistent are the relationships among the observations, including topology?
    No formal logical accuracy tests were conducted

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 as the originator(s) of the dataset and in products derived from these data. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. This information is not intended for navigational purposes.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey - ScienceBase
    Denver Federal Center, Building 810, Mail Stop 302
    Denver, CO
    USA

    1-888-275-8747 (voice)
    sciencebase@usgs.gov
  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?
  5. What hardware or software do I need in order to use the data set?
    Winzip, 7-zip, or Winrar are free software that will open .zip files

Who wrote the metadata?

Dates:
Last modified: 19-Oct-2020
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)

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