Chirp sub-bottom data collected during USGS field activity 2021-614-FA along the Palos Verdes Fault Zone

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Frequently anticipated questions:

What does this data set describe?

Title:
Chirp sub-bottom data collected during USGS field activity 2021-614-FA along the Palos Verdes Fault Zone
Abstract:
Chirp sub-bottom data were collected by the U.S. Geological Survey in May of 2021 along the Palos Verdes Fault Zone in San Pedro Bay and San Pedro Channel. MCS data were acquired coincident with chirp sub-bottom data.
Supplemental_Information:
Additional information about the field activity or activities from which these data were derived is available online at:
https://cmgds.marine.usgs.gov/fan_info.php?fan=2021-614-FA
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 dataset 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?
    Alongi, Travis, Balster-Gee, Alicia F., Kluesner, Jared W., Snyder, George R., Brothers, Daniel S., Conrad, James E., and Marcuson, Rachel K., 20240403, Chirp sub-bottom data collected during USGS field activity 2021-614-FA along the Palos Verdes Fault Zone: data release DOI:10.5066/P9HCOSDF, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

    This is part of the following larger work.

    Alongi, Travis, Balster-Gee, Alicia F., Kluesner, Jared W., Snyder, George R., Brothers, Daniel S., Conrad, James E., and Marcuson, Rachel K., 2024, Multichannel minisparker and chirp seismic reflection data collected during USGS field activity 2021-614-FA along the Palos Verdes Fault Zone: data release DOI:10.5066/P9HCOSDF, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

    Online Links:

    Other_Citation_Details:
    Suggested Citation: Alongi, T., Balster-Gee, A.F. Kluesner, J.W., Snyder, G.R., Brothers, D.S., Conrad, J.E., Marcuson, R.K., 2024, Multichannel minisparker and chirp seismic reflection data collected during USGS field activity 2021-614-FA along the Palos Verdes Fault Zone: U.S. Geological Survey data release, https://doi.org/10.5066/P9HCOSDF.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -118.54136467
    East_Bounding_Coordinate: -117.84641504
    North_Bounding_Coordinate: 33.89364486
    South_Bounding_Coordinate: 33.37643027
  3. What does it look like?
    2021-614-FA.chirp.preview.png (PNG)
    Map of Chirp tracklines acquired during USGS field activity 2021-614-FA
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 13-May-2021
    Ending_Date: 22-May-2021
    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?
      This is a Point data set. It contains the following vector data types (SDTS terminology):
      • Point (186)
    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?
    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)
    • Travis Alongi
    • Alicia F. Balster-Gee
    • Jared W. Kluesner
    • George R. Snyder
    • Daniel S. Brothers
    • James E. Conrad
    • Rachel K. Marcuson
  2. Who also contributed to the data set?
    This data collection was funded in part by the Bureau of Ocean Energy Management (BOEM) and the University of California Santa Cruz. The authors acknowledge the crew of Scripps Institution of Oceanography’s R/V Robert Gordon Sproul and all those involved in in survey planning and execution.
  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?

Chirp sub-botttom data and coincident high-resolution multichannel seismic (MCS) data were acquired during USGS field activity 2021-614-FA aboard the R/V Sproul in May of 2021. The survey was conducted in the offshore region of southern California, specifically in the inner continental borderlands tectonic region. The focus of the survey was to collect seismic lines perpendicular to the Palos Verdes Fault with close adjacent line spacing of approximately 500 meters to explore the spatial properties and distribution of faulting in the shallow subsurface. 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: 20-Dec-2022 (process 1 of 1)
    Raw SEG-Y format seismic shots were imported into Shearwater Reveal 4 (seismic software) and navigational data was converted to UTM zone 11N and stored in header bytes 81 ad 85. Further processing included: transform to envelope, water column and bottom mute, swell correction using the peak trace amplitude time averaged over the period of the swell (usually between 21 and 55 traces). Sometimes two passes of swell correction were required when there were mixed swell periods. SEG-Y files were named 2021-614-FA.chirp.###.segy where ###is the line number and 2021-614-FA is the USGS survey identifier. SEG-Y files were zipped into the file 2021-614-FA.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. Because the chirp data was collected coincident with sparker data, the sparker signature can be seen walking across some chirp profiles at various times.
  2. How accurate are the geographic locations?
    R/V Sproul uses a Furuno GP-90D (Differential GPS) positioning system with a manufacturer’s stated accuracy of 13 meters (95%). Accuracies of final products may be lower due to total propagated uncertainties of the mapping systems, which include position and motion compensation system, navigation, as well as data processing that includes calculating the source layback from the stern of the vessel.
  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 Resource_Description: These data are available in SEG-Y format (2021-614-FA.chirp.###.segy where ### is the line number) and are contained in a single zip file (2021-614-FA.chirp.zip) accompanied by CSDGM FGDC-compliant metadata.
  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?
    • Availability in digital form:
      Data format: Zip file contains the processed seismic data per navigation line. in format SEG-Y (version SEG-Y rev 1) Size: 8000
      Network links: https://doi.org/10.5066/P9HCOSDF
    • Cost to order the data: None.

  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-Apr-2024
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_P9HCOSDF/2021-614-FA.chirp.metadata.faq.html>
Generated by mp version 2.9.51 on Wed Aug 14 16:12:48 2024