Coordinates of percussion driven gravity cores collected in Alaskan lakes and fjords following the 2018 Anchorage earthquake

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Frequently anticipated questions:

What does this data set describe?

Title:
Coordinates of percussion driven gravity cores collected in Alaskan lakes and fjords following the 2018 Anchorage earthquake
Abstract:
This dataset includes coordinate information for sediment cores collected from lacustrine and fjord basins in southcentral Alaska following the 2018 Anchorage earthquake. The cores were collected with a percussion driven gravity corer for use in regional hazard assessments relating to Alaska’s seismic hazard.
Supplemental_Information:
Additional information about the field activities from which these data were derived is available online at:
https://cmgds.marine.usgs.gov/fan_info.php?fan=2021-612-FA https://cmgds.marine.usgs.gov/fan_info.php?fan=2020-615-FA https://cmgds.marine.usgs.gov/fan_info.php?fan=2020-625-FA
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this Federal Geographic Data Committee-compliant metadata file is intended to document the data set in nonproprietary form, as well as in Esri format, this metadata file may include some Esri-specific terminology.
  1. How might this data set be cited?
    Singleton, Drake M., Brothers, Daniel S., Hill, Jenna C., Haeussler, Peter J., and Witter, Robert C., 20230706, Coordinates of percussion driven gravity cores collected in Alaskan lakes and fjords following the 2018 Anchorage earthquake: data release DOI:10.5066/P924775B, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

    Online Links:

    This is part of the following larger work.

    Singleton, Drake M., Brothers, Daniel S., Hill, Jenna C., Haeussler, Peter J., and Witter, Robert C., 2023, Geophysical and core sample data collected in lakes and fjords of southcentral Alaska following the 2018 Anchorage earthquake: data release DOI:10.5066/P924775B, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

    Online Links:

    Other_Citation_Details:
    Suggested Citation: Singleton, D.M., Brothers, D.S., Hill, J.C., Haeussler, P.J., and Witter, R.C., 2023, Geophysical and core sample data collected in lakes and fjords of southcentral Alaska following the 2018 Anchorage earthquake: U.S. Geological Survey data release, https://doi.org/10.5066/P924775B.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -151.490850
    East_Bounding_Coordinate: -148.537050
    North_Bounding_Coordinate: 62.520180
    South_Bounding_Coordinate: 60.071108
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 08-Aug-2020
    Ending_Date: 22-Jun-2021
    Currentness_Reference:
    Ground conditions at time data were collected
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: point shapefile
  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. It contains the following vector data types (SDTS terminology):
      • Point (60)
    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 WGS 1984.
      The ellipsoid used is WGS 84.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257224.
  7. How does the data set describe geographic features?
    2021_612_2020_625_2020_615_core_nav.zip
    Sampling locations of cores. (Source: U.S. Geological Survey)
    FID
    Internal feature number (Source: Esri) Sequential unique numbers automatically generated
    Shape
    Feature Geometry (Source: Esri) Coordinates defining the feature
    Field1
    Naming ID of the core (Source: U.S. Geological Survey) Unique core identification assigned in the field.
    Lat
    Latitude where core was collected in decimal degrees. (Source: Onboard iPad9 GPS)
    Range of values
    Minimum:60.07948
    Maximum:62.49715
    Units:decimal degrees
    Resolution:0.00001
    Lon
    Longitude where core was collected in decimal degrees. (Source: Onboard iPad9 GPS)
    Range of values
    Minimum:-148.60677
    Maximum:-151.47024
    Units:decimal degrees
    Resolution:0.00001
    Entity_and_Attribute_Overview: Zip file of core collection locations in shapefile format.
    Entity_and_Attribute_Detail_Citation: U.S. Geological Survey

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Drake M. Singleton
    • Daniel S. Brothers
    • Jenna C. Hill
    • Peter J. Haeussler
    • Robert C. Witter
  2. Who also contributed to the data set?
    USGS PCMSC Marine Facility personnel
  3. To whom should users address questions about the data?
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    Attn: PCMSC Science Data Coordinator
    2885 Mission Street
    Santa Cruz, CA

    831-427-4747 (voice)
    pcmsc_data@usgs.gov

Why was the data set created?

Identification of fault-related submarine hazards is a primary mission of the USGS Coastal and Marine Hazards and Resources Program. Intraslab earthquakes, which occur at depth within the subducting plate, can cause intense shaking at the Earth’s surface, but do not cause surficial faulting or result in significant land level changes. The seismic shaking associated with intraslab earthquakes can remobilize subaqueous sediment and lead to gravity driven sediment flows, potentially creating a record of past shaking from these events. To gain a better understanding of the conditions that produce seismically triggered deposits in subaqueous basins the USGS collected Chirp seismic and sediment cores from several lakes and fjords following the M7.1 2018 Anchorage earthquake. These data are intended to further our understand of geologic hazard in southcentral Alaska, improve risk assessments for local communities and critical infrastructure, and to provide data for future research on regional paleoseismic records in southcentral Alaska.

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: 01-Jul-2021 (process 1 of 1)
    Cores were collected using a UWITEC percussion driven gravity corer from a variety of research vessels during field activities 2021-612-FA, 2020-625-FA, and 2020-615-FA. Latitude and longitude values were taken at the vessel’s location coincident with core contact with subaqueous substrate. Field-collected navigation data were output in shapefile format.
  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?
    Quality control of attribute accuracy was conducted during field data collection and processing workflows.
  2. How accurate are the geographic locations?
    The locations of cores were determined using an iPad9 and iPhone12 global satellite navigation system (GNSS) receiver capable of receiving signals from multiple satellite constellations. The manufacturer reported accuracy for horizontal positions is 3-5 m.
  3. How accurate are the heights or depths?
    Core location depths and water depths were not associated with a fixed vertical datum at the time of core collection. No formal positional accuracy tests were conducted, nor were they applicable for this dataset.
  4. Where are the gaps in the data? What is missing?
    Dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details.
  5. How consistent are the relationships among the observations, including topology?
    No formal logical consistency tests were conducted. It is possible that due to vessel drift during the coring process that the surface coordinates provided in this data file do match exactly with the location on the lake floor of the actual coring location. Estimated uncertainty is likely to be less than 10 meters.

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 USGS-authored or produced data and information are in the public domain from the U.S. Government and are freely redistributable with proper metadata and source attribution. Please recognize and acknowledge the U.S. Geological Survey as the originator(s) of the dataset and in products derived from these data.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey - CMGDS
    2885 Mission Street
    Santa Cruz, CA

    831-427-4747 (voice)
    pcmsc_data@usgs.gov
  2. What's the catalog number I need to order this data set? Core coordinates are provided in a shapefile format (2021_612_2020_625_2020_615_core_nav.zip) accompanied by CSDGM FGDC-compliant metadata.
  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 on any other system or for general or scientific purposes, 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: Zip file contains point shapefile of core collection locations. in format shapefile (version ArcMap 10.7) Size: 0.008
      Network links: https://doi.org/10.5066/P924775B
    • Cost to order the data: None.

  5. What hardware or software do I need in order to use the data set?
    Shapefile navigation data can be viewed using any Geographic Information System (GIS) software (for example, ArcGIS, QGIS).

Who wrote the metadata?

Dates:
Last modified: 06-Jul-2023
Metadata author:
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Attn: PCMSC Science Data Coordinator
2885 Mission Street
Santa Cruz, CA

831-427-4747 (voice)
pcmsc_data@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/pcmsc/DataReleases/CMGDS_DR_tool/DR_P924775B/2021-612_2020-625_2020-615_core_nav_metadata_052223.05-22-2023.faq.html>
Generated by mp version 2.9.51 on Wed Jul 26 11:09:59 2023