Chirp Seismic Survey Tracklines - Lake Mohave 2002

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Frequently anticipated questions:

What does this data set describe?

Title: Chirp Seismic Survey Tracklines - Lake Mohave 2002
Abstract:
Lake Mohave is one of several multi-purpose reservoirs that have been constructed on the Colorado River. The lake was formed upon completion of the Davis Dam in 1953. No mapping of the floor of the lake had been conducted since completion of the Davis Dam. The U.S. Geological Survey, in cooperation with researchers from the University of Nevada Las Vegas, completed a geophysical survey of this lake in April 2002. The survey included collection of sidescan sonar imagery of nearly the entire lake floor, and high-resolution seismic-reflection profiles along widely spaced lines throughout the lake. The detailed mapping of the lake floor was used to determine the amount of sediment that had accumulated in the lake since impoundment, its distribution, and the processes of deposition.
  1. How might this data set be cited?
    Foster, David S., and Cross, VeeAnn A., 2005, Chirp Seismic Survey Tracklines - Lake Mohave 2002: Open-File Report 2004-1247, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Cross, VeeAnn A., Foster, David S., and Twichell, David C., 2005, Lake Mohave Geophysical Survey 2002: GIS Data Release: Open-File Report 2004-1247, U.S. Geological Survey, Reston, VA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -114.711633
    East_Bounding_Coordinate: -114.570683
    North_Bounding_Coordinate: 35.868300
    South_Bounding_Coordinate: 35.200633
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 18-Apr-2002
    Ending_Date: 28-Apr-2002
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: vector digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Vector data set. It contains the following vector data types (SDTS terminology):
      • String (57)
    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 Decimal degrees. 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?
    seislines
    Information unavailable from original metadata. (Source: Information unavailable from original metadata.)
    FID
    Internal feature number. (Source: ESRI) Sequential unique whole numbers that are automatically generated.
    Shape
    Feature geometry. (Source: ESRI) Coordinates defining the features.
    ID
    Sequential number for each separate polyline. (Source: Software generated.)
    Range of values
    Minimum:0
    Maximum:56
    LINENAME
    Number refering the the line number of data acquisition. (Source: Software generated.)
    Range of values
    Minimum:1
    Maximum:60
    HOTLINK
    String field indicating the location of the images to hotlink to each line. Has a variable for the initial part of the path. (Source: User defined.) character set.
    RANGE
    The Knudsen setting determining the fire rate of the seismic system. Recorded as a range in meters instead of time. (Source: Software defined.)
    Range of values
    Minimum:50
    Maximum:100
    Units:meters

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • David S. Foster
    • VeeAnn A. Cross
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    David S. Foster
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    (508) 548-8700 x2271 (voice)
    (508) 457-2310 (FAX)
    dfoster@usgs.gov

Why was the data set created?

This shapefile is used to enable correlation between the seismic-reflection profiles and the sidescan-sonar imagery, geologic interpretation, and other features represented on the lake floor.

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: unknown (process 1 of 7)
    This particular navigation was recorded with a Knudsen chirp subbottom system. The Knudsen system stores the navigation in a file separate from the SEG-Y data. This file was reformatted using SED and AWK scripts to create a comma delimited file appropriate to be added to ArcView 3.2a as an event theme. Person who carried out this activity:
    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov
    Date: unknown (process 2 of 7)
    This event theme was then converted to a polyline shapefile using an Avenue script that converts points to lines based on a unique line identifier within the attribute table. Person who carried out this activity:
    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov
    Date: unknown (process 3 of 7)
    The attributes of JDAY and range (referring to the seismic range of the system) were added to the attribute table.
    Date: 05-Dec-2017 (process 4 of 7)
    Edits to the metadata were made to fix any errors that MP v 2.9.36 flagged. This is necessary to enable the metadata to be successfully harvested for various data catalogs. In some cases, this meant adding text "Information unavailable" or "Information unavailable from original metadata" for those required fields that were left blank. Other minor edits were probably performed (title, publisher, publication place, etc.). Attempted to modify http to https where appropriate. Modified the data citation to add series and publication information, as well as include a landing page link. Moved the horizontal quantitative accuracy information to the horizontal accuracy report. Added the standard order process section, which includes a link to the data. The metadata date (but not the metadata creator) was edited to reflect the date of these changes. The metadata available from a harvester may supersede metadata bundled within a download file. Compare the metadata dates to determine which metadata file is most recent. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 20-Jul-2018 (process 5 of 7)
    USGS Thesaurus keywords added to the keyword section. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 18-Nov-2019 (process 6 of 7)
    Crossref DOI link was added as the first link in the metadata. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 08-Sep-2020 (process 7 of 7)
    Added keywords section with USGS persistent identifier as theme keyword. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    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?
    Navigation data were collected with a PLGR system. The nominal accuracy of the system is thought to be 10m. Since the Knudsen system is a sidemount rather than towed system, this accuracy is not diminished. Assumed accuracy is 10 meters.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    Information unavailable from original metadata.
  5. How consistent are the relationships among the observations, including topology?
    Information unavailable from original metadata.

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)
    David S. Foster
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    (508) 548-8700 x2271 (voice)
    (508) 457-2310 (FAX)
    dfoster@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 publication 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: 18-Mar-2024
Metadata author:
VeeAnn A. Cross
U.S. Geological Survey
Marine Geologist
384 Woods Hole Rd.
Woods Hole, MA

(508) 548-8700 x2251 (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 person is no longer with USGS. (updated on 20240318)
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/ofr2004-1247/seislinesmeta.faq.html>
Generated by mp version 2.9.51 on Mon Mar 25 16:05:22 2024