Chirp sub-bottom data acquired offshore San Francisco and Pacifica during USGS field activity S-16-10-NC

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Frequently anticipated questions:

What does this data set describe?

Title:
Chirp sub-bottom data acquired offshore San Francisco and Pacifica during USGS field activity S-16-10-NC
Abstract:
Chirp sub-bottom data were collected by the U.S. Geological Survey in August 2010, offshore San Mateo County, California. Data were collected aboard the R/V Snavely during field activity S-16-10-NC. Chirp data were collected using an Edgetech 512 chirp sub-bottom profiler.
Supplemental_Information:
Additional information about the field activities from which these data were derived is available online at:
http://cmgds.marine.usgs.gov/fan_info.php?fan=S1610NC
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?
    Balster-Gee, Alicia F., Sliter, Ray W., Ross, Stephanie L., and Ryan, Holly F., 20231003, Chirp sub-bottom data acquired offshore San Francisco and Pacifica during USGS field activity S-16-10-NC: data release DOI:10.5066/P9ZP0CBV, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

    This is part of the following larger work.

    Balster-Gee, Alicia F., Sliter, Ray W., Ross, Stephanie L., and Ryan, Holly F., 2023, Minisparker and chirp seismic-reflection data acquired offshore San Francisco and Pacifica during USGS field activity S-16-10-NC: data release DOI:10.5066/P9ZP0CBV, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

    Online Links:

    Other_Citation_Details:
    Suggested Citation: Balster-Gee, A.F., Sliter, R.W., Ross, S.L., Ryan, H.F., 2023, Minisparker and chirp seismic reflection data acquired offshore San Francisco and Pacifica during USGS field activity S-16-10-NC: U.S. Geological Survey data release, https://doi.org/10.5066/P9ZP0CBV.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -122.47924
    East_Bounding_Coordinate: -122.63016
    North_Bounding_Coordinate: 37.75645
    South_Bounding_Coordinate: 37.47502
  3. What does it look like?
    S-16-10-NC.chirp.preview.png (PNG)
    Map of chirp sub-bottom profiles acquired during USGS field activity S-16-10-NC
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 05-Aug-2010
    Ending_Date: 08-Aug-2010
    Currentness_Reference:
    ground condition at time data were collected
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: 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 stored in the SEG-Y data trace headers in header bytes 73 and 77.
    2. What coordinate system is used to represent geographic features?
      The map projection used is WGS 1984 UTM Zone 10N.
      Projection parameters:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -123.0
      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.
      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: 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)
    • Alicia F. Balster-Gee
    • Ray W. Sliter
    • Stephanie L. Ross
    • Holly F. Ryan
  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

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

Why was the data set created?

This work was funded by the USGS Coastal and Marine Geology Program’s Coastal and Marine Catastrophic Hazards project . These sub-bottom profiles provide shallow geologic structure, stratigraphy and fault geometry information for the San Gregorio, San Andreas, and Golden Gate faults to be used to update the USGS Quaternary fault database and to use in shaking-hazard models developed by the Working Group for California Earthquake probabilities. Other objectives of the mission were to determine thickness of Holocene sediments and to verify surficial mapping. These data and information are intended for science researchers, students, policy makers, and the 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: 24-Aug-2010 (process 1 of 2)
    Chirp sub-bottom data were collected using an Edgetech 512 sub-bottom profiler system. Data were recorded in SEG-Y 32-bit floating point format.
    Date: 01-Aug-2022 (process 2 of 2)
    SEG-Y format chirp traces were imported into Shearwater Reveal seismic software for processing. Navigation was converted to UTM zone 10N and stored in header bytes 73 and 77. Processing steps include: water column mute, two passes of swell correction over 51 traces and over 101 traces, minimum phase wavelet filtering, spiking deconvolution, top and bottom mute, 100ms AGC and output to SEG-Y format. SEG-Y files were zipped into a single zip file (S-16-10-NC.chirp.zip).
  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?
    Quality control was conducted during acquisition. Some seismic profiles have gaps in them due to system crashes or intentional shutdowns as required, under terms of our operating permit, to protect marine mammals. Minor swell correction artifacts exist at line starts and ends as well as in areas where seafloor amplitudes are low.
  2. How accurate are the geographic locations?
    Position data were provided by a Hemisphere V100 Global Positioning System using L1, C/A code and carrier phase smoothing with a stated accuracy of 60 centimeters.
  3. How accurate are the heights or depths?
  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.
  5. How consistent are the relationships among the observations, including topology?
    Quality control was conducted during acquisition and processing to ensure consistency of SEG-Y header navigation and seismic-reflection data that matches bathymetry along the tracklines.

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 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 - CMGDS
    2885 Mission Street
    Santa Cruz, CA

    831-427-4747 (voice)
    pcmsc_data@usgs.gov
  2. What's the catalog number I need to order this data set? These data are available in SEG-Y format in a single zip file (S-16-10-NC.chirp.zip).
  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?
    Use of SEG-Y data requires specialized software, such as ProMax and Seisworks by Landmark Geophysical; FOCUS and SeisX by Paradigm Geophysical; SPW by Parallel Geoscience; VISTA by Seismic Image Software; SeiSee by Dalmorneftegeophysica (DMNG); amongst others.

Who wrote the metadata?

Dates:
Last modified: 03-Oct-2023
Metadata author:
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Attn: PCMSC Science Data Coordinator
2885 Mission Street
Santa Cruz, CA

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/DataReleases/CMGDS_DR_tool/DR_P9ZP0CBV/S-16-10-NC.chirp.metadata.faq.html>
Generated by mp version 2.9.51 on Thu Oct 5 16:14:41 2023