JPEG images of seismic data collected off the southern shore of Martha's Vineyard, MA, 2007

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Frequently-anticipated questions:

What does this data set describe?

Title:
JPEG images of seismic data collected off the southern shore of Martha's Vineyard, MA, 2007
Abstract:
The USGS Woods Hole Science Center conducted a nearshore geophysical survey offshore of the southern coast of Martha's Vineyard, in the vicinity of the Martha's Vineyard Coastal Observatory (MVCO) in August 2007. This mapping program was part of a larger research effort supporting the Office of Naval Research (ONR) Ripples Directed-Research Initiative (DRI) studies at MVCO by providing data collection and modeling. The geophysical data will be used to provide initial conditions for wave and circulation models for the study area. Ultimately, geophysical mapping, oceanographic measurements and modeling will help to improve our understanding of coastal sediment-transport processes.

The geophysical mapping utilized a suite of high-resolution instrumentation to map the surficial sediment distribution, depth and sub-surface geology: dual-frequency 100/500 KHz sidescan-sonar system, 234-KHz interferometric sonar, and 500 Hz -12 KHz chirp sub-bottom profiler. The survey was conducted aboard the M/V Megan Miller August 9-13, 2007. The study area covers 35 square kilometers from about 0.2 km to 5-km offshore of the south shore of Martha's Vineyard, and ranges in depth from ~ 5 to 20 meters.

  1. How should this data set be cited?

    U.S. Geological Survey, 2009, JPEG images of seismic data collected off the southern shore of Martha's Vineyard, MA, 2007: Open-File Report 2008-1288, U.S. Geological Survey, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Denny, J.F., Danforth, W.W., Foster, D.S., and Sherwood, C.R., 2009, Geophysical Data Collected off the South Shore of Martha's Vineyard, Massachusetts: Open-File Report 2008-1288, U.S. Geological Survey, Woods Hole.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -70.600292
    East_Bounding_Coordinate: -70.511213
    North_Bounding_Coordinate: 41.347370
    South_Bounding_Coordinate: 41.301252

  3. What does it look like?

    <https://pubs.usgs.gov/of/2008/1288/GIS_catalog/Seisimage/seisimage_sm.jpg> (JPEG)
    JPEG image of seismic-reflection profile

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

    Beginning_Date: 09-Aug-2007
    Ending_Date: 13-Aug-2007
    Currentness_Reference: ground condition

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

    Geospatial_Data_Presentation_Form: raster digital data

  6. How does the data set represent geographic features?

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

      This is a Raster data set. It contains the following raster data types:

      • Dimensions, type Pixel

    2. What coordinate system is used to 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? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

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

    Jane Denny
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700x2311 (voice)
    5084572310 (FAX)
    jdenny@usgs.gov

Why was the data set created?

JPEG images of each seismic profile were generated in order to incorporate images of the seismic data into Geographic Information System (GIS) projects and data archives utilizing HTML. These JPEG images represent 680 km of seismic data collected in 2007. This format is universal and yields an easily viewable image of the seismic profiles. Each profile image is hyperlinked to its corresponding trackline navigation contained within a polyline shapefile (seismic_trknav.shp), shot-point locations are available in a point shapefiles (seismic__500sht.shp, seismic__100sht.shp, and seismic__sht.shp). These data are available in an ESRI ArcMap project, as well as separate .zip archives (<https://pubs.usgs.gov/pubs/of/2008/1288/GIS_catalog/>).

How was the data set created?

  1. From what previous works were the data drawn?

    (source 1 of 1)
    .

    Source_Contribution:
    Approximately 680 km of high-resolution chirp seismic-reflection profiles were collected using an EdgeTech Geo-Star FSSB sub-bottom profiling system and an SB-0512i towfish (0.5-12 kHz) mounted on a catamaran and towed off the stern of the R/V Megan Miller. Edgetech J-Star seismic acquisition software was used to control the Geo-Star topside unit and digitally log trace data in the EdgeTech JSF format (<http://www.edgetech.com/productlinemarine.html>). Data were acquired using a 0.25-s shot rate, 5-ms pulse length and a 0.5-to-8.0 kHz swept frequency. Recorded trace lengths were approximately 250-ms. Trackline spacing varied from 40 meters in water depths less than 15 meters to 70-meter spacing in water depths greater than 15 meters. Shore perpendicular tracklines spacing ranged from 500 m to 1 km apart.

  2. How were the data generated, processed, and modified?

    Date: 2007 (process 1 of 2)
    A C program, jsf2segy, created at the USGS Woods Hole was used to convert the Edgetech JSF format files to SEG-Y. Scripts utilizing SIOSEIS (version 2007.8) were then executed in order to remove sea surface heave and mute the water column within seismic traces by: 1)automatically picking the sea floor by identifying peak amplitudes within a vertical window; 2)smoothing sea floor picks using an along track filter approximating the period of sea surface heave (the filter window was set to use 60 traces); 3)creating a series of difference values between the raw and smoothed seafloor picks for each trace; 4)shifting traces up or down according to the difference values; and 5) muting each trace between time zero and the time of the smoothed sea floor pick, thus removing noise within the water column. Changes to the traces within each profile were saved to new "heave corrected" SEG-Y files. An additional SIOSEIS script was executed to apply an automatic gain control (AGC) to the heave corrected SEG-Y files, resulting in more uniform amplitudes throughout the record (SIOSEIS, 2007).

    Software: SIOSEIS 2007.8

    Person who carried out this activity:

    Dave Foster
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700x2271 (voice)
    5084572310 (FAX)
    dfoster@usgs.gov

    Date: 2007 (process 2 of 2)
    A C-Shell script using Seismic Unix (version 4.1) to read the SEG-Y files and plot the data as 8-bit gray scale Postscript files using the Seismic Unix 'psimage' algorithm was then executed. All images were created with a horizontal scale of 200 traces per inch. The profiles contain 50 milliseconds of Two-Way Travel Time within an 8-inch vertical window, yielding 6.25 milliseconds per inch. Postscript images were converted to JPEG format using the UNIX ImageMagick (version 5.5.6).

    Software: Seismic Unix 4.1, ImageMagick 5.5.6

    Person who carried out this activity:

    Dave Foster
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700x2271 (voice)
    5084572310 (FAX)
    dfoster@usgs.gov

  3. What similar or related data should the user be aware of?

    Henkart, Paul, 2007, SIOSEIS: Scripps Institution of Oceanography, University of California - San Diego, LaJolla, CA.

    Online Links:

    Stockwell, John, 2007, Seismic Un*x: Center for Wave Phenomena - Colorado School of Mines, Golden, CO.

    Online Links:

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?

    The EdgeTech SB-0512i was towed approximately 5 meters astern and approximately 1.5 meters below the sea surface. A GPS navigation receiver was mounted on the seismic sled to provide seismic navigation. GPS positions were sent, via radio modem, to a receiver positioned on the aft roof of the acquisition van aboard the R/V Megan Miller. GPS positions were sent directly to the EdgeTech J-Star seismic acquisition software. The horizontal accuracy of GPS is assumed to be ± 10 m (<http://www.navcen.uscg.gov/>).

  3. How accurate are the heights or depths?

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

    All acquired seismic data were processed and JPEG images produced. Line 92 was saved as l91f1_001 during acquisition.

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

    Processed seismic data were converted to JPEG format for ease of seismic trace display. Quality control was conducted during processing.

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:
The U.S. Geological Survey asks to be referenced as the originator of the dataset in any future publications.

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

    Jane Denny
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700x2311 (voice)
    5084572310 (FAX)
    jdenny@usgs.gov

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

    Downloadable Data

  3. What legal disclaimers am I supposed to read?

    Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials.

    Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

  4. How can I download or order the data?

  5. Is there some other way to get the data?

    Digital copies of these chirp seismic data may also be obtained in the SEG-Y Rev. 1 standard format upon request. The data would be packaged on DVD, and contain the chirp-processed, envelope traces.

  6. What hardware or software do I need in order to use the data set?

    These JPEG data can be viewed with any image viewing software.

Who wrote the metadata?

Dates:
Last modified: 05-Oct-2009
Last Reviewed: 2009
Metadata author:
Jane Denny
U.S. Geological Survey
Geologist
384 Woods Hole Rd.
Woods Hole, MA 02543-1598

(508) 548-8700x2311 (voice)
5084572310 (FAX)
jdenny@usgs.gov

Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:

Generated by mp version 2.8.25 on Mon Oct 05 15:30:59 2009