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