Reprocessed multichannel seismic reflection data acquired offshore Southern California during USGS field activity O-1-99-SC

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Frequently anticipated questions:

What does this data set describe?

Title:
Reprocessed multichannel seismic reflection data acquired offshore Southern California during USGS field activity O-1-99-SC
Abstract:
Multichannel seismic (MCS) data were collected by the U.S. Geological Survey (USGS) in June of 1999 in the coastal zone and continental shelf between Los Angeles and San Diego, offshore California (USGS field activity O199SC). In 2021 these data were reprocessed to improve accuracy and resolvability of geologic structures and fault systems of California’s continental 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=O199SC
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?
    Alongi, Travis, Balster-Gee, Alicia F., Kluesner, Jared W., and Sliter, Ray W., 20221115, Reprocessed multichannel seismic reflection data acquired offshore Southern California during USGS field activity O-1-99-SC: data release DOI:10.5066/P9GR0PWF, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -118.605396
    East_Bounding_Coordinate: -117.242340
    North_Bounding_Coordinate: 33.869064
    South_Bounding_Coordinate: 32.605396
  3. What does it look like?
    O199SC.MCSTracklineMap.png (PNG)
    Map of MCS tracklines acquired during USGS field activity O-1-99-SC offshore Southern California.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 05-Jun-1999
    Ending_Date: 17-Jun-1999
    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 (66)
    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?
    O199SC.mcs.segy.zip
    Zip archive of seismic shots with time stamp in standard SEG-Y file format (Source: Society of Exploration Geophysicists (SEG) Technical Standards, available for download at http://seg.org/Publications/SEG-Technical-Standards)
    O199SC.mcs.trackline.shapefile.zip
    Zip file contains a polyline shapefile (.shp) of the location of each SEG-Y shot point along the navigated tracklines and associated files (Source: U.S. Geological Survey)
    LINE
    Number of navigation line (Source: Assigned unique line identifier name) Producer-asssigned unique line identifier name
    Entity_and_Attribute_Overview:
    Seismic Shots with Time Stamp in standard SEG-Y file format, with trackline navigation presented in polyline shapefile 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
    • Ray W. Sliter
  2. Who also contributed to the data set?
    Reprocessing efforts were supported by an Interagency Agreement (IAA) between the Bureau of Ocean Energy Management (BOEM) and the U.S. Geological Survey. The authors acknowledge Danny Brothers (USGS) and Mark Leung (BOEM) for their role in coordinating the IAA. The authors also acknowledge the participants of the field activity O-1-99-SC, the crew of the R/V Ocean Olympic 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?

MCS data were acquired to support the Southern California Earthquake Hazards project to help mitigate earthquake and tsunami hazards for the Southern California region by improving our understanding of how deformation is distributed (spatially and temporally) in the offshore with respect to the onshore region. The reprocessed dataset enhances the seismic data quality which will be useful for future research on the geomorphic, sedimentary and tectonic record offshore California. These data 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?
    original seismic-reflection data (source 1 of 1)
    Sliter, Ray W., Normark, William R., and Gutmacher, Christina E., 2000, Multichannel seismic-reflection data acquired off the coast of southern California-Part A 1997, 1998, 1999, and 2000: U.S. Geological Survey, online.

    Online Links:

    Type_of_Source_Media: online database
    Source_Contribution: seismic shot SEG-Y data and navigation for reprocessing
  2. How were the data generated, processed, and modified?
    Date: 17-Jun-1999 (process 1 of 3)
    Multichannel seismic-reflection data were acquired using a 35/35 cubic inch double chamber gas injector (GI) gun firing every 12 seconds at 3000 psi and a 24-channel ITI streamer with 10-meter group spacing. Seismic data were recorded with a STRATAVIEW digital recording system in SEG-D format on 2-GB DAT tapes using a 1-millisecond sample rate and a 3-second record length. A 60-Hz notch filer was used. Navigation data was simultaneously recorded in YoNav. SEG-D to SEG-Y conversion was performed at sea on a Sun workstation running ProMax seismic processing software. Data sources used in this process:
    • original seismic-reflection data
    Date: 15-Dec-2019 (process 2 of 3)
    Original SEG-Y shot point navigation was lost in a server crash. Navigation was repopulated to the headers of raw pre-stack ASCII ship navigation. The header navigation fix was performed in a python script using segyio (https://github.com/equinor/segyio) where the start time and end time of each line was used extract the data from the navigation file. A parametric interpolation (x and y as a function of time) was done so that an x/y location could be determined for each trace based on time. The GPS position from the navigation file was assumed to be mid-ship.
    Date: 20-May-2020 (process 3 of 3)
    Raw pre-stack SEG-Y data was imported into Reveal seismic software (https://www.shearwatergeo.com/4/reveal-software, v. 10.4.2019), where geometry was applied and data were binned at 5-meters. A 15-30-500-600 Hz bandpass filter and trim statics were applied prior to semblance analysis. Moveout velocities were calculated in 300 CMP increments and with with significant geology changes. Prestack predictive deconvolution (0ms gap length, 75 ms operator, 3 percent whitening designed 500ms below the water bottom time and over 21 traces), trim statics applied after NMO using picked velocities and a water column mute were applied prior to stacking. Post-stack phase shift time migration was applied at 80 percent of picked velocities and the water column was muted. Data were exported to SEG-Y format with navigation in standard header byte locations and zipped into O199SC.mcs.segy.zip. CMP navigation was converted from points to a multi-line shapefile in QGIS-LTR (v. 3.21) and zipped into O199SC.mcs.trackline.shapefile.zip.
  3. What similar or related data should the user be aware of?
    Normark, W.R., Reid, J.A., Sliter, R.W., Holton, D., Gutmacher, C.E., Fisher, M.A., and Childs, J.R., 1999, Cruise Report for 01-99-SC: Southern California Earthquake Hazards Project.

    Online Links:

    Other_Citation_Details:
    Normark, W.R., Reid, J.A., Sliter, R.W., Holton, D., Gutmacher, C.E., Fisher, M., A., and Childs, J.R., 1999, Cruise Report for 01-99-SC: Southern California Earthquake Hazards Project: U.S. Geological Survey Open-File Report 99-560, http://pubs.usgs.gov/of/1999/0560/.
    Fisher, Michael A., Langenheim, Victoria E., Nicholson, Craig, Ryan, Holly F., and Sliter, Ray W., 2000, Recent developments in understanding the tectonic evolution of the Southern California offshore area: Implications for earthquake-hazard analysis.

    Other_Citation_Details:
    Fisher, M.A., Langenheim, V.E., Nicholson, C., Ryan, H.F., and Sliter, R.W., 2009, Recent developments in understanding the tectonic evolution of the Southern California offshore area: Implications for earthquake-hazard analysis, in Lee, H.J., and Normark, W.R., (eds.) Earth Science in the Urban Ocean: The Southern California Continental Borderland: Geological Society of America Special Papers, v. 454, https://doi.org/10.1130/2009.2454(4.2).

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.
  2. How accurate are the geographic locations?
    YoNav system worked well, using GPS input to provide position data every six seconds for 24 hrs/day. The preferred mode of operation was differential GPS, and there were minimal problems with the shore-based reference stations during the survey. Most of the periods without differential GPS were limited to a few minutes or tens of minutes. The logged intervals of degraded positional control generally indicate periods when there were sporadic position determinations that could be in error by as much as 10,000 km, suggesting both bad data input and failure of YoNav to filter out bad data. Further positional error resulted from lost prestack navigation from server crash. Repopulated navigation headers of raw pre-stack data for survey from USGS navigation file /nav/o-1-99-sc.061. The header navigation fix was performed in a python script using the python package segyio (https://github.com/equinor/segyio). We used the start time and end time of each line to extract the data from the navigation file. A parametric interpolation (x and y as a function of time) was done so that an x/y location could be determined for each trace based on time.
  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. Seismic data are unavailable where GI gun failed on Julian Day 162 and where marine mammal observers determined mammals were within the 250-m shutdown radius.
  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. Navigation data are available as a trackline shapefile in the ‘Data Files’ section. Trackline navigation combines SEG-Y line parts into a single-track line (47 tracklines and 66 SEG-Y files, including parts).

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 O199SC.mcs.segy.zip containing 66 standard SEG-Y format files of seismic shots with time stamp (Society of Exploration Geophysicists (SEG) Technical Standards, available for download at http://seg.org/Publications/SEG-Technical-Standards). A shapefile of the SEG-Y shot-track navigation is available in the zip file O199SC.mcs.trackline.shapefile.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?
    • Availability in digital form:
      Data format: Zip file (O199SC.mcs.segy.zip) contains the processed seismic data per navigation line. in format SEG-Y (version SEG-Y rev 1) Size: 1780
      Network links: https://doi.org/10.5066/P9GR0PWF
      Data format: Zip file contains a shapefile with SEG-Y trackline navigation in format shapefile (version ArcGIS Pro (version 2.4.1)) Size: 0.6179
      Network links: https://doi.org/10.5066/P9GR0PWF
    • 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 Reveal by Shearwater; 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. Users must have software capable of reading shapefile (.shp) format to use the shot point shapefile.

Who wrote the metadata?

Dates:
Last modified: 15-Nov-2022
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_P9GR0PWF/O199SC_metadata.faq.html>
Generated by mp version 2.9.51 on Thu Nov 17 17:43:41 2022