Isostatic Gravity Map of the Death Valley Ground-Water Model Area, Nevada and California

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Frequently anticipated questions:

What does this data set describe?

Title:
Isostatic Gravity Map of the Death Valley Ground-Water Model Area, Nevada and California
Abstract:
An isostatic gravity map of the Death Valley groundwater model area was prepared from over 40,0000 gravity stations as part of an interagency effort by the U.S. Geological Survey and the U.S. Department of Energy to help characterize the geology and hydrology of southwest Nevada and parts of California.
  1. How might this data set be cited?
    Ponce, D.A., Blakely, R.J., Morin, R.L., and Mankinen, E.A., 2001, Isostatic Gravity Map of the Death Valley Ground-Water Model Area, Nevada and California: U.S. Geological Survey Miscellaneous Field Studies Map MF-2381-C, U.S. Geological Survey, Denver, Colorado.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -118.000
    East_Bounding_Coordinate: -115.000
    North_Bounding_Coordinate: 38.250
    South_Bounding_Coordinate: 35.000
  3. What does it look like?
    http://pubs.usgs.gov/mf/2002/mf-2381/mf-2381-c/mf-2381-c.pdf (PDF)
    graphical representation of map
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2001
    Currentness_Reference:
    publication date
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: map
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a point data set.
    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 0.00001. Longitudes are given to the nearest 0.00001. Latitude and longitude values are specified in Decimal Degrees. The horizontal datum used is North American Datum of 1927.
      The ellipsoid used is CLARKE 1866.
      The semi-major axis of the ellipsoid used is 6378206.4.
      The flattening of the ellipsoid used is 1/294.98.
  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)
    • Ponce, D.A.
    • Blakely, R.J.
    • Morin, R.L.
    • Mankinen, E.A.
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    Jeremiah B. Workman
    U.S. Geological Survey
    Box 25046 Denver Federal Center, MS-913
    Denver, CO
    U.S.A.

    303-236-1257 (voice)
    jworkman@usgs.gov

Why was the data set created?

This dataset was completed in support of the Death Valley Ground-Water Basin regional flow model funded by the U.S. Department of Energy in conjunction with the U. S. Geological Survey and U.S. National Park Service. The proposed model is intended to address issues concerning the availability of water in Death Valley National Park and surrounding counties of Nevada and California and the migration of contaminants out of the Nevada Test Site and Yucca Mountain high-level waste repository.

How was the data set created?

  1. From what previous works were the data drawn?
    Mankinen and others, 1998 (source 1 of 3)
    Mankinen, E.A., Hildenbrand, T.G., Roberts, C.W., and Davidson, J.G., 1998, Principal facts for new gravity stations in the Pahute Mesa and Oasis Valley areas, Nevada: U.S. Geological Survey Open-File Report 98-498, U.S. Geological Survey, Denver, CO.

    Type_of_Source_Media: paper
    Source_Contribution: reference
    Morin and Blakely, 1999 (source 2 of 3)
    Morin, R.L., and Blakely, R.J., 1999, Principal facts for about 500 gravity stations in the vicinity of Amargosa Desert and Pahrump Valley, California and Nevada: U.S. Geological Survey Open-File Report 99-31, U.S. Geological Survey, Denver, CO.

    Type_of_Source_Media: paper
    Source_Contribution: reference
    Ponce, 1997 (source 3 of 3)
    Ponce, D.A., 1997, Gravity data of Nevada: U.S. Geological Survey Digital Data Series DDS-42, U.S. Geological Survey, Denver, CO.

    Type_of_Source_Media: disc
    Source_Contribution: reference
  2. How were the data generated, processed, and modified?
    Date: 1999 (process 1 of 4)
    data compiled
    Date: 2000 (process 2 of 4)
    data reviewed
    Date: 2001 (process 3 of 4)
    data published
    Date: 15-Nov-2001 (process 4 of 4)
    Creation of original metadata record Person who carried out this activity:
    Jeremiah B. Workman
    U.S. Geological Survey
    Box 25046 Denver Federal Center, MS-913
    Denver, CO
    USA

    303-236-1257 (voice)
    jworkman@usgs.gov
  3. What similar or related data should the user be aware of?
    Ponce, D.A., and Blakely, R.J., 2001, Aeromagnetic Map of the Death Valley Ground-Water Model Area, Nevada and California: U.S. Geological Survey Miscellaneous Field Studies Map MF-2381-D, U.S. Geological Survey, Denver, Colorado.

    Online Links:

    Blakely, R.J., and Ponce, D.A., 2001, Map Showing Depth to Pre-Cenozoic Basement in the Death Valley Ground-Water Model Area, Nevada and California: U.S. Geological Survey Miscellaneous Field Studies Map MF-2381-E, U.S. Geological Survey, Denver, Colorado.

    Online Links:

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    Observed gravity data are accurate to about 0.05 milligals.
  2. How accurate are the geographic locations?
    Accuracy of the data is about 18 m.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    This map was produced to be used at a map scale of 1:250,000.
  5. How consistent are the relationships among the observations, including topology?
    Gravity anomalies were visually checked and reviewed at a scale of 1:250,000.

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)
    U.S. Geological Survey
    Central Publications Group
    Box 25046
    Denver Federal Center, MS-902
    Denver, CO

    303-236-5486 (voice)
  2. What's the catalog number I need to order this data set?
  3. What legal disclaimers am I supposed to read?
    Although this digital spatial data has been subjected to rigorous review and is substantially complete, it is released on the condition that neither the USGS nor the United States Government may be held liable for any damage resulting from its authorized or unauthorized use.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 13-Jun-2016
Metadata author:
Peter N Schweitzer
USGS Midwest Area
Collection manager, USGS Geoscience Data Clearinghouse, http://geo-nsdi.er.usgs.gov/
Mail Stop 954
12201 Sunrise Valley Dr
Reston, VA
USA

703-648-6533 (voice)
703-648-6252 (FAX)
pschweitzer@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://geo-nsdi.er.usgs.gov/metadata/map-mf/2381/c/metadata.faq.html>
Generated by mp version 2.9.48 on Tue Jul 03 20:05:12 2018