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

Frequently anticipated questions:

• What does this data set describe?
  1. How might this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
• Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
• Why was the data set created?
• How was the data set created?
  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  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?
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
  5. How consistent are the relationships among the data, including topology?
• How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
• Who wrote the metadata?

What does this data set describe?

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:

   • https://doi.org/10.5066/F74T6GF1
   • https://www.sciencebase.gov/catalog/item/57322719e4b0dae0d5dc1f3f

   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:

   • https://doi.org/10.5066/F74T6GF1

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?
   • Availability in digital form:

     Data format:	zip file contains the processed seismic data in format SEG-Y (version SEG-Y rev 1) Size: 1870.0
     Network links:	https://www.sciencebase.gov/catalog/file/get/57322719e4b0dae0d5dc1f3f https://doi.org/10.5066/F74T6GF1

   • Cost to order the data: None

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)