Chirp Seismic-Reflection data from the John Day Reservoir

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Frequently-anticipated questions:

What does this data set describe?
    Title: Chirp Seismic-Reflection data from the John Day Reservoir
    Abstract:
    A two-week field operation was conducted in the John Day Reservoir on the Columbia River to image the floor of the pool, to measure the distribution and thickness of post-impoundment sediment, and to verify these geophysical data with video photography and bottom sediment samples. The field program was a cooperative effort between the USGS Coastal and Marine Geology Team of the Geologic Division and the USGS Columbia River Research Laboratory of the Biological Resources Division. The data collection was completed aboard the R/V ESTERO during September 13-27, 2000. The interest in sediment accumulation in the reservoir was two-fold. First, it was unknown how effective this reservoir was as a sediment trap to material that otherwise would have been transported down-river to the estuary and eventually to the ocean. The recent erosion of beaches along the Washington coast has been attributed to a decreased contribution of sediment from the Columbia River to the coastal system due to the damming of the river. Second, sediment accumulation on the floors of reservoirs along the Columbia River has been suggested to be diminishing salmon spawning grounds. The extent of changes in habitat since construction of the John Day Dam, however, had not been documented. Common data sets were needed to address both of these questions, and for these reasons this geophysical and sampling program was undertaken.

  1. How should this data set be cited?

    Cross, VeeAnn A. , and Twichell, David C. , 2004, Chirp Seismic-Reflection data from the John Day Reservoir:.

    This is part of the following larger work.

    Cross, VeeAnn A. , and Twichell, David C. , 2004, Geophysical, Sedimentologic, and Photographic Data from the John Day Reservoir, Washington and Oregon: Data Archive and Preliminary Discussion: Open-File Report 2004-1014, U.S. Geological Survey, Woods Hole Science Center, Woods Hole, MA.

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -120.69
    East_Bounding_Coordinate: -119.3
    North_Bounding_Coordinate: 45.943
    South_Bounding_Coordinate: 45.686

  3. What does it look like?

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

    Beginning_Date: 11-Sep-2000
    Ending_Date: 22-Sep-2000
    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?

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

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 11
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -117.000000
      Latitude_of_Projection_Origin: +00.000000
      False_Easting: 500000
      False_Northing: 0

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 20
      Ordinates (y-coordinates) are specified to the nearest 20
      Planar coordinates are specified in meters

      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 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.

  7. How does the data set describe geographic features?

    Entity_and_Attribute_Overview:
    The chirp seismic subbottom data was collected with the SIS-1000 sidescan and seismic system. The transducer for the seismics is mounted on the towfish with the data collected logged on a TritonElics QMIPS computer system. The seismic data was separated from the raw data file and converted to the SEG-Y format using the Unix program "qmipstosegy". The seismic data were then further processed using SeismicUnix to filter and add gain to the data as well as output a format for printing. Test line 1 and lines 1-7, and lines 37-40 were collected at a 0.8 second fire rate. Test line 3 and lines 8-36 were collected at a 0.530 fire rate. Due to the limitations of "qmipstosegy", the navigation information stored in the SEG-Y headers is all UTM, zone 11, WGS84. The study area actually covers zones 10 and 11, but for consistency, all values are in zone 11. Seismic test lines and line 1-7 did not have the pressure depth sensor functioning. The value for depth was coming from the Hypack navigation system which was hardwired at 3m. Seismic lines 8-40 should have the pressure depth value from the sensor. However, the value reported appeared to be too shallow. The hardwired depth value from Hypack during these data collections lines was 1.5 m - the actual measured depth of the fish. Additional information of use - the chirp length on the 0.800 second fire rate is 20 ms, and 12 ms on the 0.530 second fire rate.

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?

    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov

Why was the data set created?
The chirp seismic-reflection profiles were collected to measure the thickness and distribution of sediment that has accumulated in the John Day Reservoir since impoundment in 1968.

How was the data set created?
  1. From what previous works were the data drawn?

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

    (process 1 of 2)
    The chirp seismic subbottom data was collected with the SIS-1000 sidescan and seismic system. The transducer for the seismics is mounted on the towfish with the data collected logged on a TritonElics QMIPS computer system. The seismic data was separated from the raw data file and converted to the SEG-Y format using the USGS Unix program "qmipstosegy".

    Person who carried out this activity:

    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov

    (process 2 of 2)
    The seismic data were then further processed using SeismicUnix to filter and add gain to the data as well as output a format for printing. Lines 1-7, and lines 37-40 were collected at a 0.8 second fire rate. Lines 8-36 were collected at a 0.530 fire rate.

    Person who carried out this activity:

    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov

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 navigation was collected with a P-Code plugger navigation system. Although the navigation antenna was mounted on the ship rather than the towfish, the system was towed shallow and extremely close to the boat therefore making the "layback" error negligible. Because of the high fire rates of the system, each "shot" does not have a navigation point, therefore these values have to be interpolated.

  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 observations, including topology?

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 must be referenced as the originator of the dataset in any future products or research derived from these data.

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

    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@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?

    These data were prepared by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed in this report, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof. Any views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof. Although all data published in this report have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related materials and/or the functioning of the software. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of this data, software, or related materials.

  4. How can I download or order the data?

Who wrote the metadata?
Dates:
Last modified: 09-Mar-2004

Metadata author:
VeeAnn A. Cross
U.S. Geological Survey
Marine Geologist
384 Woods Hole Rd.
Woods Hole, MA 02543-1598

(508) 548-8700 x2251 (voice)
(508) 457-2310 (FAX)
vatnipp@usgs.gov

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

Metadata extensions used:

Generated by mp version 2.7.3 on Tue Mar 09 13:54:12 2004