Seismotectonic maps in the vicinity of the lower Wabash Valley, Illinois, Indiana, and Kentucky - Digital Spatial Database: Structure contours on Cambrian-Precambrian unconformity

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Frequently anticipated questions:


What does this data set describe?

Title:
Seismotectonic maps in the vicinity of the lower Wabash Valley, Illinois, Indiana, and Kentucky - Digital Spatial Database: Structure contours on Cambrian-Precambrian unconformity
Abstract:
This cover contains structure contours of the elevations of the unconformity at the Cambrian-Precambrian boundary. These data were contributed by Glenn Bear of Indiana University as part of the work on his doctoral thesis. The southern part of the map was produced by James Drahovzal of the Kentucky Geological Survey and merged with Bear's map of the rest of the map area and beyond. Public and proprietary seismic reflection and well data were used to define the structure. Units are in thousands of feet below sea level.
A prominent east-west structure in the southern half of the map area is the western end of the Rough Creek Graben. At its deepest point the unconformity is more than 30,000 ft (9,100 m) below sea level. Faulted strata at this depth mean that the Rough Creek Fault System penetrates to hypocentral depths.
At the western edge of the map area, the graben bends to the southwest into the Reelfoot Rift and becomes more shallow. North of the Rough Creek Graben, and extending northward along the Wabash River, is the Wabash Valley Fault System. This fault system cuts an elliptical low in the unconformity. Some of the structure contours show horizontal offsets at depths that are opposite to the offsets expected from the known normal slip on the faults. Some authors interpret this as evidence of strike slip motion on these faults.
This cover contains all the contours including the extents outside the map area. "bcontours" is clipped to the map area.
  1. How might this data set be cited?
    Rhea, Susan, 1997, Seismotectonic maps in the vicinity of the lower Wabash Valley, Illinois, Indiana, and Kentucky - Digital Spatial Database: Structure contours on Cambrian-Precambrian unconformity: U.S. Geological Survey Open-File Report 97-0681, U.S. Geological Survey, Denver, CO.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -89
    East_Bounding_Coordinate: -87
    North_Bounding_Coordinate: 39
    South_Bounding_Coordinate: 36.5
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: Cambrian-Precambrian
    Currentness_Reference:
    This is the most recent interpretation of the structure of the Cambrian-Precambrian unconformity in the map area (1997).
  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 Vector data set. It contains the following vector data types (SDTS terminology):
      • Point (35)
      • String (413)
      • GT-polygon composed of chains (0)
    2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitude and longitude values are specified in Decimal Degrees. The horizontal datum used is Unknown.
      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?
    BCONTOURS.PAT
    attributes of point symbols (Source: Rhea)
    SYMBOL
    code for symbol used to plot syncline, anticline features (Source: Rhea)
    ValueDefinition
    120 
    121 
    123 
    124 
    BCONTOURS.AAT
    attributes of contour lines (Source: Rhea, Bear)
    DEPTH
    depth to Cambrian-PreCambrian unconformity, in thousands feet below sea level (Source: Bear)
    Range of values
    Minimum:-30
    Maximum:-6
    Units:thousands of feet below sea level
    Resolution:1
    SYMBOL
    code for symbol used to plot contours (Source: Rhea)
    ValueDefinition
    202 
    203 
    204 

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Rhea, Susan
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    Susan Rhea
    US Geological Survey
    Geophysicist
    MS966, Box 25046, Federal Center
    Denver, CO
    USA

    303-273-8639 (voice)
    303-273-8600 (FAX)
    rhea@usgs.gov
    Contact_Instructions: email is the best way to make contact

Why was the data set created?

The data was generated to help in understanding the seismotectonic hazards in the vicinity of the lower Wabash Valley. This data complements similar data collected in the vicinity of New Madrid, MO US Geological Survey Open-File Report 95-0574, available at http://pubs.usgs.gov/of/1995/0574/

How was the data set created?

  1. From what previous works were the data drawn?
    (source 1 of 2)
    Bear, G.W., and Drahovzal, J.A., written communication.

    Other_Citation_Details:
    Bear mapped structure in the northern part of the map area for his dissertation at Indiana University. Drahovzal mapped structure in the southern part for a planned Kentucky Geological Survey map. Bear combined both maps into one and sent us the digital files.
    Type_of_Source_Media: paper, electronic mail system
    Source_Scale_Denominator: 250000
    Source_Contribution:
    Authors sent digital coordinates of contours via email and paper copy of map with depth contours via surface mail.
    (source 2 of 2)
    Bear, G.W., Rupp, J.A., and Rudman, A.J., 1997, Seismic interpretation of the deep structure of the Wabash Valley Fault System: Seismological Research Letters 68/4, Seis. Soc. America.

    Other_Citation_Details:
    p 624-640. This paper discusses only the north-central part of the map area.
  2. How were the data generated, processed, and modified?
    Date: 30-Jul-1997 (process 1 of 2)
    Coordinates of contour lines were received via ftp, and a paper map was received via surface mail. Contour lines were converted to an arcinfo coverage and depth values were added by hand while comparing lines on the paper map to the digital view. Values assigned to contour lines were reviewed by Bear. Clipped from bcontours_all.
    Date: 06-May-1998 (process 2 of 2)
    Creation of original metadata record Person who carried out this activity:
    Susan Rhea
    US Geological Survey
    Geophysicist
    MS966, Box 25046, Federal Center
    Denver, CO
    USA

    303-273-8639 (voice)
    303-273-8600 (FAX)
    rhea@usgs.gov
    Contact_Instructions: email is the best way to make contact
  3. What similar or related data should the user be aware of?
    Wheeler, Russell L., Rhea, Susan, Diehl, Sharon F., Drahovzal, James A., Bear, Glenn W., and Sargent, Michael L., 1997, Seismotectonic map showing faults, igneous rocks, and geophysical and neotectonic features in the vicinity of the lower Wabash Valley, IL, IN, and KY: U.S. Geological Survey Miscellaneous Investigations Series Map I-2583-D, U.S. Geological Survey, Denver, CO.

    Other_Citation_Details: pamphlet accompanies map

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?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    data contains all contours and depths
  5. How consistent are the relationships among the observations, including topology?
    Chain-node topology present.

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)
    Susan Rhea
    US Geological Survey
    Geophysicist
    USGS Mail Stop 966
    Box 25046, Federal Center
    Denver, CO
    USA

    303-273-8639 (voice)
    303-273-8600 (FAX)
    rhea@usgs.gov
    Contact_Instructions: Email is the best way to make contact.
  2. What's the catalog number I need to order this data set? USGS Open-File Report 97-0681
  3. What legal disclaimers am I supposed to read?
    This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards and stratigraphic nomenclature. Any use of trade names is for descriptive purposes only and does not imply endorsement by the USGS.
  4. How can I download or order the data?
  5. What hardware or software do I need in order to use the data set?
    ARC/INFO version 7.0.3 or later or ArcView 3.0 or later

Who wrote the metadata?

Dates:
Last modified: 10-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:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://geo-nsdi.er.usgs.gov/metadata/open-file/97-681/bcontours.faq.html>
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