Chirp sub-bottom data collected offshore Northern California during USGS field activity 2019-643-FA

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Frequently anticipated questions:

What does this data set describe?

Title:
Chirp sub-bottom data collected offshore Northern California during USGS field activity 2019-643-FA
Abstract:
Chirp sub-bottom data were collected by the U.S. Geological Survey in 2019 offshore Humboldt County of northern California to expand data coverage along the southern Cascadia Margin.
Supplemental_Information:
Additional information about the field activity from which these data were derived is available online at:
https://cmgds.marine.usgs.gov/fan_info.php?fan=2019-643-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?
    Balster-Gee, Alicia F., Hill, Jenna C., Watt, Janet T., Brothers, Daniel S., Nieminski, Nora M., Alongi, Travis, Hatcher, Gerald A., and Nasr, Brandon, 20230720, Chirp sub-bottom data collected offshore Northern California during USGS field activity 2019-643-FA: data release DOI:10.5066/P998EC72, 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., Hill, Jenna C., Watt, Janet T., Brothers, Daniel S., Nieminski, Nora M., Alongi, Travis, Hatcher, Gerald A., and Nasr, Brandon, 2023, Multichannel minisparker seismic-reflection and chirp subbottom data collected offshore Northern California during USGS field activity 2019-643-FA: data release DOI:10.5066/P998EC72, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

    Online Links:

    Other_Citation_Details:
    Suggested Citation: Balster-Gee, A.F., Hill, J.C., Watt, J.T., Brothers, D.S., Nieminski, N.M., Alongi, T., Hatcher, G.A., and Nasr, B., 2023, Multichannel minisparker seismic-reflection and chirp subbottom data collected offshore Northern California during USGS field activity 2019-643-FA: U.S. Geological Survey data release, https://doi.org/10.5066/P998EC72
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -124.71130
    East_Bounding_Coordinate: -124.27460
    North_Bounding_Coordinate: 41.573364
    South_Bounding_Coordinate: 40.655668
  3. What does it look like?
    2019-643-FA.MCS.preview.png (PNG)
    Map of MCS profiles acquired during USGS field activity 2019-643-FA.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 27-Sep-2019
    Ending_Date: 10-Oct-2019
    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 provided and stored in the SEG-Y data trace headers in header bytes 81 and 85 locations.
    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
  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
    • Jenna C. Hill
    • Janet T. Watt
    • Daniel S. Brothers
    • Nora M. Nieminski
    • Travis Alongi
    • Gerald A. Hatcher
    • Brandon Nasr
  2. Who also contributed to the data set?
    Data collection efforts were supported in part by an Interagency Agreement (IAA) between the Bureau of Ocean Energy Management (BOEM) and the U.S. Geological Survey. The authors acknowledge the crew of the M/V Bold Horizon and 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?

This dataset contains processed Chirp sub-bottom data collected by the U.S. Geological survey during field activity 2019-643-FA aboard the M/V Bold Horizon. Data were acquired to characterize offshore faults and to study sediment distribution. Chirp data were collected coincidently with multichannel seismic-reflection data (MCS) and were used to determine sediment core targets for marine geohazard studies. These data and information are intended for science researchers, students, 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: 25-Feb-2021 (process 1 of 1)
    The Discover acquisition software (v. 6) output envelope chirp data in SEG-Y format. Sioseis seismic software (https://sioseis.ucsd.edu/) was used to correct for the chirp towfish depth. Data were then swell corrected over a period of 21 traces and the water column was muted. Processed data were exported to SEG-Y format with standard header byte locations. X and Y navigation points are written to header bytes 81/85 and 73/77 in UTM zone 10N coordinates. SEG-Y data files were compressed into the zip file 2019-643-FA.chirp.segy.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?
    +/- 0.6m 95 percent confidence (DGPS) (http://dev.wr.usgs.gov/idb/media/service_materials/2022/12/07/101121522789/Hemisphere_V100specsheet.pdf)
  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? SEG-Y data are available in the zip file 2019-643-FA.chirp.zip that contains 43 standard SEG-Y format files of seismic traces with time stamp (Society of Exploration Geophysicists (SEG) Technical Standards, available for download at http://seg.org/Publications/SEG-Technical-Standards). SEG-Y files are named 2019-643-FA.chirp.##.chirp.sgy where ## is the line name and 2019-643-FA is the USGS field activity identifier.
  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: 15800
      Network links: https://doi.org/10.5066/P998EC72
    • 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: 20-Jul-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_P998EC72/2019-643-FA.chirp.metadata.faq.html>
Generated by mp version 2.9.51 on Thu Aug 3 17:49:39 2023