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Open-File Report 2006-1373

High-resolution boomer seismic-reflection profiles of the shelf off southern California from cruise A-1-00-SC: Santa Monica Bay to San Diego

Frequently Anticipated Questions

Metadata also available as - [Outline] - [Parseable text] - [XML]

Frequently-anticipated questions:

What does this data set describe?

Title:
High-resolution boomer seismic-reflection profiles of the shelf off southern California: Santa Monica Bay to San Diego
Abstract:
High-resolution boomer data were collected in the California Continental Borderland as part of the southern California Earthquake Hazards Task of the Southern California Coastal and Marine Geology Regional Investigations Project. During the period from 1997 to 2002, five data-acquisition cruises collected seismic-reflection data using several different systems from offshore Santa Barbara, California, south to the Exclusive Economic Zone boundary with Mexico. A key mission of this project was to map late Quaternary deformation in addition to improving our understanding of which offshore fault zones might have potential to damage highly populated areas of southern California. State regulations concerning the use of seismic-reflection equipment within three miles of the coastline precluded the routine gathering of high-resolution multichannel data in that swath adjacent to the coast. Boomer seismic-reflection data, however, can be obtained within the State 3-mile limit provided the operation receives authorization from the California State Lands Commission.

The Geopulse boomer data accessible through this report were collected on the cruise A-1-00-SC, which was the only survey where we requested permission to work inside the 3-mile limit of the State of California. These data are critical to the job of connecting onshore and offshore faults, the overall lengths of which are related to the potential size of an earthquake that might be generated along them. The 2000 survey was designed to fill the gap between the coast and reflection data obtained in deeper water on previous cruises as well as data anticipated from future surveys. This report includes trackline maps showing the location of the data, as well as both digital data files (SEG-Y) and images of all of the profiles.

  1. How should this data set be cited?

    Gutmacher, Christina E. , Ross, Stephanie L. , Triezenberg, Peter, Sliter, Ray W. , Normark, William R. , and Edwards, Brian D. , 2006, High-resolution boomer seismic-reflection profiles of the shelf off southern California: Santa Monica Bay to San Diego: USGS Open-File Report USGS OFR 2006-1373, United States Geological Survey, Menlo Park, California.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -119.00000
    East_Bounding_Coordinate: -117.00000
    North_Bounding_Coordinate: +34.50000
    South_Bounding_Coordinate: +32.50000

  3. What does it look like?

    <http://pubs.usgs.gov/of/2006/1373/images/A-1-00-SC.kmz> (Google Earth Keyhole Markup Language (KML) file)
    Interactive index map of tracklines covered in this report.
    <http://pubs.usgs.gov/of/2006/1373/images/A-1-00-SC.pdf> (PDF)
    Static index map of tracklines covered in this report.
    <http://pubs.usgs.gov/of/2006/1373/jpg/delph/a1g0h802.jpg> (JPEG)
    Example of Geopulse seismic data accessible via this report.
    <http://pubs.usgs.gov/of/2006/1373/pdf/delph/a1g0h802.pdf> (PDF)
    Example of Geopulse seismic data accessible via this report.

  4. Does the data set describe conditions during a particular time period?

    Beginning_Date: 05-Jun-2000
    Ending_Date: 29-Jun-2000
    Currentness_Reference: Time span of data collection and initial archiving.

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form:
    Text report containing graphical map images and geophysical data images (no spatial referencing).

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

    2. What coordinate system is used to represent geographic features?

      Grid_Coordinate_System_Name: other grid system
      Other_Grid_System's_Definition:
      Cylindrical equidistant with central meridian -118.0 degrees longitude

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 3
      Ordinates (y-coordinates) are specified to the nearest 3
      Planar coordinates are specified in seconds

      The horizontal datum used is World Geodetic System 1984.
      The ellipsoid used is WGS 84.
      The semi-major axis of the ellipsoid used is 6378137.
      The flattening of the ellipsoid used is 1/298.257.

  7. How does the data set describe geographic features?

    Entity_and_Attribute_Overview:
    Locations of data profiles are shown as a line segment in Google Earth. Click on the start of the trackline to open a pop-up window and view details of the trackline, download data and view a preview of the reflection profile. The full-size JPEG reflection profile can be viewed and the JPEG, PDF, and SEG-Y digital data can be downloaded from this pop-up window. Alternatively, the user can note a trackline number on the static map, then find the number in the data table, and view and/or download the data from the table.
    Entity_and_Attribute_Detail_Citation: none

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

    • Christina E. Gutmacher
    • Stephanie L. Ross
    • Peter Triezenberg
    • Ray W. Sliter
    • William R. Normark
    • Brian D. Edwards

  2. Who also contributed to the data set?

    Peter Triezenberg produced the interactive web pages for this report.

  3. To whom should users address questions about the data?

    Ray W. Sliter
    United States Geological Survey (USGS)
    Geophysicist
    USGS, Mail Stop 999, 345 Middlefield Road
    Menlo Park, CA 94025-3561
    USA

    (650) 329-5194 (voice)
    rsliter@usgs.gov

Why was the data set created?

These MCS data were collected as part of a project to identify the active fault systems in the southern California coastal zone, including the continental shelf and adjacent deep basins, that pose the greatest potential seismic hazards for the most populated urban corridor along the U.S. Pacific margin. See <http://walrus.wr.usgs.gov/cabrillo/tierra/index.html> for more information. This report is prepared to make these data available to science researchers, students, and other interested parties. Supplemental_Information: Additional information for this USGS Coastal and Marine Geology field activity is available online at <http://walrus.wr.usgs.gov/infobank/a/a100sc/html/a-1-00-sc.meta.html>.

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: 2003 (process 1 of 4)
    Refer to report sections "Data acquisition method" and "Data processing" for details of Geopulse boomer data acquisition and processing sequence used for data in this report. Ray W. Sliter

    Date: 2003 (process 2 of 4)
    Plotted shot-point map of cruises using GMT <http://gmt.soest.hawaii.edu/> to create static map. Converted plots to PDF and JPEG files to provide format options for downloading data. Ray W. Sliter

    Date: 2006 (process 3 of 4)
    Used GEODAS (GEOphysical DAta System) to create a custom bathymetric and topographic grid for the southern California region covered by the cruise index map. The website is: <http://www.ngdc.noaa.gov/mgg/geodas/geodas.html>. The parameters used are as follows: Grid database: US Coastal Relief Model Grids Lat/Lon Area Bounds: 34.50000 N to 32.50000 N, 119.00000 W to 117.00000 W Grid Cell Size: 3 seconds Grid Cell Value Parameters: 4-byte integers, 10ths of meters Grid Format: xyz (lon, lat, depth) format, no header, space-delimited, exclude empty cells. Peter Triezenberg

    Date: 2006 (process 4 of 4)
    Plotted tracklines of seismic reflection profiles using GMT <http://gmt.soest.hawaii.edu/> to create static map. Plotted tracklines of seismic reflection profiles using a Keyhole Markup Language (KML) file in Google Earth. Peter Triezenberg

  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?

    Data have not been independently verified.

  2. How accurate are the geographic locations?

    Shot point numbers in the data files correspond to those in the navigation files. The horizontal positional accuracy of the seismic data thus linked to ship's position is estimated to be within 30 meters.

  3. How accurate are the heights or depths?

    Depths shown in the seismic data files are in seconds (round trip travel time) and are referenced to sea level.

  4. Where are the gaps in the data? What is missing?

    Reference the full report for a description of data coverage. All single-channel Geopulse data collected on the referenced cruise have been included in this report. Some seismic profiles have gaps in them due to system crashes or hardware maintenance.

  5. How consistent are the relationships among the observations, including topology?

    Undetermined.

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:
These data are not intended for navigational purposes. Please recognize the U.S. Geological Survey (USGS) as the source of this information.

  1. Who distributes the data set? (Distributor 1 of 1)

    Ray W. Sliter
    United States Geological Survey (USGS)
    USGS, Mail Stop 999, 345 Middlefield Road
    Menlo Park, CA 94025-3561
    USA

    (650) 329-5194 (voice)
    rsliter@usgs.gov

  2. What's the catalog number I need to order this data set?

    United States Geological Survey Open-File Report 2006-1373 This report is distributed on-line only. Access it at <http://pubs.usgs.gov/of/2006/1373/>.

  3. What legal disclaimers am I supposed to read?

    Please recognize the U.S. Geological Survey (USGS) as the source of this information.

    Although these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, these data and information are provided with the understanding that they are not guaranteed to be usable, timely, accurate, or complete. Users are cautioned to consider carefully the provisional nature of these data and information before using them for decisions that concern personal or public safety or the conduct of business that involves substantial monetary or operational consequences. Conclusions drawn from, or actions undertaken on the basis of, such data and information are the sole responsibility of the user.

    Neither the U.S. Government nor any agency thereof, nor any of their employees, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any data, software, information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights.

    Trade, firm, or product names and other references to commercial products and services are provided for information only and do not constitute endorsement or warranty, express or implied, by the USGS, USDOI, or U.S. Government, as to their suitability, content, usefulness, functioning, completeness, or accuracy.

  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 29-Jun-2006
Metadata author:
Ray W. Sliter
United States Geological Survey (USGS)
Geophysicist
USGS, Mail Stop 999, 345 Middlefield Road
Menlo Park, CA 94025-3561
USA

(650) 329-5194 (voice)
rsliter@usgs.gov

Metadata standard:
Content Standard for Digital Geospatial Metadata ("CSDGM version 2") (FGDC-STD-001-1998)

Generated by mp version 2.8.11 on Fri Jul 14 14:22:05 2006
For more information contact: Ray Sliter

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