Archive of Boomer seismic reflection data collected aboard RV CORLISS cruise CRLS97007 off northern Oregon and southern Washington inner continental shelf

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Frequently anticipated questions:

What does this data set describe?

Title:
Archive of Boomer seismic reflection data collected aboard RV CORLISS cruise CRLS97007 off northern Oregon and southern Washington inner continental shelf
Abstract:
This CD-ROM contains digital high resolution seismic-reflection and bathymetric data collected during the USGS CORLISS 97007 cruise during Aug. 27 to Sept. 13, 1997. The study area covers the inner and middle continental shelf extending 150 km along the coast from Tillamook Head, OR northward past the mouth of the Columbia River to Point Grenville, WA. Seismic data were collected along a grid of track lines run parallel and perpendicular to the coast that were spaced about 5 km apart. The seismic-reflection data are stored as SEG-Y standard format that can be read and manipulated by most seismic processing software. Much of the information specific to the data are contained in the headers of the SEG-Y format files. The file system format is ISO 9660 which can be read with DOS, Unix, and MAC operating systems with the appropriate CD-ROM driver software installed. The navigation and bathymetric data are stored as an ASCII file with the navigation and depth information logged mostly at a 10 second interval. When the fathometer was not operating the depth field is replaced with a value of 9999. Depths are presented in meters from the sea surface (assuming a speed of sound in water of 1450 m/sec). Both raw and tidally corrected depths are present in the navigation file.
  1. How might this data set be cited?
    Cross, VeeAnn A., Twichell, David C., Parolski, Kenneth F., and Harrison, Scott E., 1998, Archive of Boomer seismic reflection data collected aboard RV CORLISS cruise CRLS97007 off northern Oregon and southern Washington inner continental shelf: Open-File Report 98-351, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Cross, V.A., Twichell, D.C., Parolski, K.F., and Harrison, S.E., 1998, Archive of Boomer seismic reflection data collected aboard RV CORLISS cruise CRLS97007 off northern Oregon and southern Washington inner continental shelf: U.S. Geological Survey Open-File Report 98-351, https://doi.org/10.3133/ofr98351 . This is actually a set of 2 CD-ROMs.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -124.5
    East_Bounding_Coordinate: -123.8
    North_Bounding_Coordinate: 47.6
    South_Bounding_Coordinate: 46.9
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 27-Aug-1997
    Beginning_Time: 2004 GMT
    Ending_Date: 13-Sep-1997
    Ending_Time: 2220 GMT
    Currentness_Reference:
    ground condition of data acquisition.
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      Indirect_Spatial_Reference:
      Horizontal coordinate units for X and Y are in seconds of arc from Greenwich and the Equator for each shot location and are located in the SEG-Y trace headers. The separate navigation file is in geographic.
    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 0.0001. Longitudes are given to the nearest 0.0001. Latitude and longitude values are specified in Degrees and decimal minutes. 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.
      The flattening of the ellipsoid used is 1/298257.
      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: assumed sea level
      Altitude_Resolution: 1
      Altitude_Distance_Units: two-way travel time
      Altitude_Encoding_Method: Attribute values
      Depth_System_Definition:
      Depth_Datum_Name: local surface (sea level)
      Depth_Resolution: 1
      Depth_Distance_Units: meters
      Depth_Encoding_Method: Attribute values
  7. How does the data set describe geographic features?
    allnav.txt
    Tab-delimited text file of the compilation of all the navigation collected on the cruise. Contains 36683 data records. (Source: Producer defined.)
    Jdtime
    Julian day, hour, minute, second (times are in GMT) (Source: Producer defined) text
    Lon
    Longitude of the navigation fix with the negative indicating the western hemisphere. The data is in the format degrees decimal minutes with the degress designated by a 'd'. For example -124d05.6850 (Source: Producer defined) text
    Lat
    Latitude of the navigation fix with the postive value indicating the northern hemisphere. The data is in the format degrees decimal minutes with the degress designated by a 'd'. For example 46d55.3220 (Source: Producer defined) text
    Unc_depth
    Edited file of uncorrected and unaveraged depths - there were a lot of bad values that had to be deleted. These bad values were replaced with 9999 which represents a no data value. (Source: Producer defined.)
    Range of values
    Minimum:5
    Maximum:160.7
    Units:meters
    Smooth
    Edited values of uncorrected but averaged depths. A 10 point running average was applied to the bathymetric data to assist in removing the surface swell. Values of 9999 are no data values. (Source: Producer defined.)
    Range of values
    Minimum:5.33
    Maximum:158.1
    Units:meters
    Source
    Data source of the bathymetric value - 1 indicates collected in the field, a value of 2 indicates the value was digitized off the analog 3.5kHz record. (Source: Producer defined.)
    ValueDefinition
    1Collected in the field using the fathometer.
    2The value was digitized off the analog 3.5kHz record
    Tide_Cor
    Tide corrected depths using the averaged values. The correction used a weighted average of the Toke Point and Astoria tide stations. A value of 9999 indicates no data. (Source: Producer defined)
    Range of values
    Minimum:3.67
    Maximum:156.81
    Units:meters
    line
    Seismic line number. Blank value indicates no seismic data acquisition at that point. (Source: Producer defined.) text
    shot#
    Seismic shot number. Blank value indicates no seismic data acquisition at that point. (Source: Producer defined.)
    Range of values
    Minimum:1
    Maximum:28320
    Units:shot
    Entity_and_Attribute_Overview:
    The data were acquired using a Huntec electro-mechanical sound source powered by an ORE or EG+G power supply and ITI or Benthos streamer as the receiver. Seismic data were logged digitally with the EPC ADS-640 acquisition system. The field data were reformatted to SEG-Y format and were checked for quality with the SEISMIC UNIX seismic processing software and are archived on this CD-ROM. The SEG-Y format is described in detail by Barry and others (1975). The files are standard 16-bit unsigned integer SEG-Y format. The SEG-Y files consist of shot files with one trace per shot. There are 2048 samples per trace. The sample interval is 61 microsec. which resulted in a trace length of 125 ms. The boomer was fired mostly at a rate of 0.5 seconds.
    Entity_and_Attribute_Detail_Citation:
    Barry, K.M., Cavers, D.A., and Kneale, C.W., 1975, Recommended standards for digital tape formats, in Digital Tape Standards; Society of Exploration Geophysicists ["Recommended standards for digital tape formats" reprinted from Geophysics, v. 32, p. 1073 - 1084; v. 37, p. 36-44; v. 40, p. 344 - 352.] p. 22 - 30. Cohen, J.K., and Stockwell, Jr. J.W., 1997, CWP/SU: Seismic Unix Release 1.6: a free package for seismic research and processing, Center for Wave Phenomena, Colorado School of Mines.

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • VeeAnn A. Cross
    • David C. Twichell
    • Kenneth F. Parolski
    • Scott E. Harrison
  2. Who also contributed to the data set?
    Seafloor Mapping Group
  3. To whom should users address questions about the data?
    Twichell, Dave
    U.S. Geological Survey
    Seafloor Mapping Project
    U.S. Geological Survey
    Woods Hole Field Center
    384 Woods Hole Road
    Quissett Campus
    Woods Hole, MA
    USA

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

Why was the data set created?

A 21-day field operation was conducted on the inner and middle continental shelf off the northern Oregon and southern Washington coast during which approximately 1200 line km of seismic-reflection, sidescan-sonar, and bathymetric data were acquired to generate reconnaissance maps of the seafloor geology and the shallow subsurface stratigraphy of this shelf environment. The Columbia River has provided huge amounts of sediment to this shelf during the Holocene transgression. Previous studies have mapped the distribution and thickness of this modern deposit on the middle and outer shelf (Nittrauer, 1978; Wolf and others, 1997), however, the distribution of this deposit on the inner shelf and its link to the adjacent coastal environment were not as clearly understood because of incomplete data coverage on the innermost shelf. Although sidescan-sonar imagery has been collected off the mouth of the Columbia River, no reconnaissance coverage was available for the entire area. Additionally, the most recent bathymetric survey of this area was completed during the 1920s (National Ocean Service, 1983). Anthropogenic activity within the Columbia River drainage basin (agriculture, logging, construction of dams, and dredging of the estuary mouth) may have altered the sediment discharge from the river which, in turn, may be affecting sediment distribution on the shelf and in adjacent coastal environments. The seismic-reflection data in concert with sidescan-sonar imagery and bathymetry collected along the same survey lines will provide an overall synthesis of the sea floor environment including the Holocene stratal geometry, the distribution of different sediment types, the distribution of mobile bedforms, outcrops of Pleistocene and older strata, and the locations of faults. The goal of this project is to provide a regional synthesis of the offshore geology to support a wide variety of management decisions and to provide a basis for further process-oriented investigations. The project is conducted cooperatively with the Washington State Department of Ecology.

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: Sep-1997 (process 1 of 2)
    The subbottom data were recorded on the EPC Labs, Inc. ADS-640 data logging system in EPC 8-bit format. The data were converted from EPC format to SEG-Y format using the epc2segy conversion program provided by EPC, Labs Inc. The data were filtered with a low pass of 200-300 Hz and a high pass of 2000-3000 Hz at the acquisition step along with 26-55 db gain. An ITI hydrophone was used on lines 1-29 during the first 10 days of the cruise, and the acquisition was set for 26-32 db gain. A Benthos hydrophone was used on lines 30-47 collected during the last 8 days of the cruise, and the acquisition was set for 38-44 db gain for most of this time. Person who carried out this activity:
    Twichell, Dave
    U.S. Geological Survey
    Seafloor Mapping Project
    U.S. Geological Survey
    Woods Hole Field Center
    384 Woods Hole Road
    Quissett Campus
    Woods Hole, MA
    USA

    (508) 548-8700 (voice)
    (508) 457-2310 (FAX)
    dtwichell@usgs.gov
    Date: 13-Aug-2025 (process 2 of 2)
    Edited the metadata to improve formatting and remove errors flagged by MP 2.9.50. Edits include, but are not limited to: Added various fields such as series information to be consistent with other metadata produced by Woods Hole Coastal and Marine Science Center. Updated several field to more accurate information (currentness reference, status, etc.). Added additinal information to the completeness report; set the spatial reference to geographic to coincide with the navigation text file. The original spatial reference information was:
    Planar:
    Grid_Coordinate_System: Grid_Coordinate_System_name: Geographic
    Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: coordinate pair
    Coordinate_Representation: Abscissa_Resolution: 10 Ordinate_Resolution: 10 Planar_Distance_Units: seconds of arc
    Added a detailed entity and attribute section to describe the navigation text file. Removed blank elements. Updated the distribution liability to an FSP approved statement. A persistent identifier (PID) was added to the metadata in the thesaurus section. (20250813) Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    (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?
  2. How accurate are the geographic locations?
    The ship was navigated with P-CODE GPS
  3. How accurate are the heights or depths?
    The vertical position was local sea level for the depth measurements. Tide correction was applied during processing, but the datum corrected to was unspecified in the report (so unsure if it was mean sea level, mean lower low water etc.). The navigation text file (allnav.txt) contains the original depth values, edited depth values, smoothed depth values and the tide corrected depths.
  4. Where are the gaps in the data? What is missing?
    archive of SEG-Y format seismic data collected on the cruise. The following are a list of data not available: no line 7, section 1; no line 8 section 1, Line 8, section 3 is shown as L9S1 on the trackline map, misnamed in the field (should be L9S1); no line 11 section 1; no line 18, section 1; no navigation for line 27 section 4; no line 39 section 2.
  5. How consistent are the relationships among the observations, including topology?
    The SEG-Y files were plotted in the field using SEISMIC-UNIX seismic 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 none
  1. Who distributes the data set? (Distributor 1 of 1)
    Soderberg, Nancy
    U.S. Geological Survey
    Data Library
    U.S. Geological Survey
    Woods Hole Field Center
    384 Woods Hole Road
    Quissett Campus
    Woods Hole, MA
    USA

    (508) 548-8700 (voice)
    (508) 457-2310 (FAX)
    nsoderberg@usgs.gov
  2. What's the catalog number I need to order this data set? U.S. Geological Survey CD-ROM Open-File Report Data Archive
  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 for other purposes, nor on all computer systems, 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: SEG-Y in format ISO 9660 CD-ROM (version ISO 9660) Size: 650
      Network links: https://doi.org/10.3133/ofr98351
      Media you can order: CD-ROM (format ISO 9660)
      Note: UNIX, DOS, MAC
      Data format: ZIP file containing the full CD-ROM contents with a separate ZIP file for Disc 1 and Disc 2. The size reflects the first CD, while the second CD is 290 MB. in format ZIP Size: 650
      Network links: https://doi.org/10.3133/ofr98351
      Data format: ZIP file containing the full CD-ROM contents with a separate ZIP file for Disc 1 and Disc 2. The size reflects the first CD, while the second CD is 290 MB. in format SEG-Y Size: 650
      Network links: https://doi.org/10.3133/ofr98351
      Data format: ZIP file containing the full CD-ROM contents with a separate ZIP file for Disc 1 and Disc 2. The size reflects the first CD, while the second CD is 290 MB. in format TEXT Size: 650
      Network links: https://doi.org/10.3133/ofr98351
    • Cost to order the data: none

Who wrote the metadata?

Dates:
Last modified: 13-Aug-2025
Metadata author:
Twichell, Dave
U.S. Geological Survey
Seafloor Mapping Group
U.S. Geological Survey
Woods Hole Field Center
384 Woods Hole Road
Quissett Campus
Woods Hole, MA
USA

(508) 548-8700 (voice)
(508) 457-2310 (FAX)
whsc_data_contact@usgs.gov
Contact_Instructions:
The metadata contact email address is a generic address in the event the metadata contact is no longer with the U.S. Geological Survey.
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/open_file_report/ofr1998-351/ofr98-351_metadata.faq.html>
Generated by mp version 2.9.51 on Thu Aug 14 10:49:56 2025