Metadata: Identification_Information: Citation: Citation_Information: Originator: Drake M. Singleton Originator: Daniel S. Brothers Originator: Jenna C. Hill Originator: Peter J. Haeussler Originator: Robert C. Witter Publication_Date: 20230706 Title: Computed tomography (CT) scans of percussion driven gravity cores collected in Alaskan lakes and fjords following the 2018 Anchorage earthquake Geospatial_Data_Presentation_Form: JPG format images Series_Information: Series_Name: data release Issue_Identification: DOI:10.5066/P924775B Publication_Information: Publication_Place: Pacific Coastal and Marine Science Center, Santa Cruz, California Publisher: U.S. Geological Survey Online_Linkage: https://doi.org/10.5066/P924775B Larger_Work_Citation: Citation_Information: Originator: Drake M. Singleton Originator: Daniel S. Brothers Originator: Jenna C. Hill Originator: Peter J. Haeussler Originator: Robert C. Witter Publication_Date: 2023 Title: Geophysical and core sample data collected in lakes and fjords of southcentral Alaska following the 2018 Anchorage earthquake Series_Information: Series_Name: data release Issue_Identification: DOI:10.5066/P924775B Publication_Information: Publication_Place: Pacific Coastal and Marine Science Center, Santa Cruz, CA Publisher: U.S. Geological Survey 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. Online_Linkage: https://doi.org/10.5066/P924775B Description: Abstract: This dataset includes computed tomography (CT) scans of 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. Purpose: 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. 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. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20200808 Ending_Date: 20210622 Currentness_Reference: Ground conditions at time data were collected Status: Progress: In work Maintenance_and_Update_Frequency: As needed Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -151.490850 East_Bounding_Coordinate: -148.537050 North_Bounding_Coordinate: 62.520180 South_Bounding_Coordinate: 60.071108 Keywords: Theme: Theme_Keyword_Thesaurus: USGS Metadata Identifier Theme_Keyword: USGS:b24575fa-2c9d-4039-a740-9b94975bf06a Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: inlandWaters Theme_Keyword: oceans Theme_Keyword: geoscientificInformation Theme: Theme_Keyword_Thesaurus: Data Categories for Marine Planning Theme_Keyword: substrate Theme: Theme_Keyword_Thesaurus: USGS Thesaurus Theme_Keyword: core analysis Theme: Theme_Keyword_Thesaurus: Marine Realms Information Bank (MRIB) keywords Theme_Keyword: sediment Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: U.S. Geological Survey Theme_Keyword: USGS Theme_Keyword: Coastal and Marine Hazards and Resources Program Theme_Keyword: CMHRP Theme_Keyword: Pacific Coastal and Marine Science Center Theme_Keyword: PCMSC Place: Place_Keyword_Thesaurus: Geographic Names Information System (GNIS) Place_Keyword: Pacific Ocean Place_Keyword: Prince William Sound Place_Keyword: Passage Canal Place_Keyword: State of Alaska Place_Keyword: Skilak Lake Place_Keyword: Kenai Lake Place_Keyword: Tustumena Lake Place_Keyword: Chelatna Lake 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. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey, Pacific Coastal and Marine Science Center Contact_Person: PCMSC Science Data Coordinator Contact_Address: Address_Type: mailing and physical Address: 2885 Mission Street City: Santa Cruz State_or_Province: CA Postal_Code: 95060 Contact_Voice_Telephone: 831-427-4747 Contact_Electronic_Mail_Address: pcmsc_data@usgs.gov Native_Data_Set_Environment: Computed tomography (CT) scans were obtained with a Geotek RXCT system. Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: Quality control of attribute accuracy was conducted during field data collection and processing workflows. Logical_Consistency_Report: The ruler alongside the TIFF images are not corrected for sediment compaction and are relative to the beginning of the CT-scanner core track. Completeness_Report: Dataset will be updated to include additional CT-scans collected during these field activities as those cores are processed through the sediment core lab at the Pacific Coastal and Marine Science Center. Users are advised to read the rest of the metadata record carefully for additional details. Lineage: Process_Step: Process_Description: For field activities 2020-625-FA and 2020-615-FA sediment cores were collected via a percussion driven gravity corer from a variety of research vessels. The cores were transported back to the USGS Pacific Coastal and Marine Science Center core lab for subsequent analyses. Cores over 1.5 m in length were split into multiple sections to permit scanning in a Geotek RXCT X-ray tomography system. Two representative sections in each core along the XZ and YZ axes were output from the full 3D CT volumes. Images from the CT scanner had ruler scales appended using the Geotek Add Ruler v 1.4 software. Process_Date: 20201101 Process_Step: Process_Description: For CT scans of cores collected during field activities 2020-625-FA and 2020-615-FA a signal reduction algorithm, needed to address oversaturation of original scans, was applied via Geotek LASR software. Output files have LASR designation appended to file name. Process_Date: 20210201 Process_Step: Process_Description: For field activity 2021-612-FA sediment cores were collected via a percussion driven gravity corer from a converted cataraft. The cores were transported back to the USGS Pacific Coastal and Marine Science Center core lab for subsequent analyses. Cores over 1.5 m in length were split into multiple sections to permit scanning in a Geotek RXCT X-ray tomography system. Two representative sections in each core along the XZ and YZ axes were output from the full 3D CT volumes. Images from the CT scanner had ruler scales appended using the Geotek Add Ruler v 1.4 software. Process_Date: 20210801 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Point Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Point Point_and_Vector_Object_Count: 108 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Geographic: Latitude_Resolution: 0.00001 Longitude_Resolution: 0.00001 Geographic_Coordinate_Units: Decimal Degrees Geodetic_Model: Horizontal_Datum_Name: WGS 1984 Ellipsoid_Name: WGS 84 Semi-major_Axis: 6378137.0 Denominator_of_Flattening_Ratio: 298.257224 Entity_and_Attribute_Information: Overview_Description: Entity_and_Attribute_Overview: Zip folder of CT scans of sediment cores. Images are in JPG format and include scans for both XZ and YZ directional slices. Naming convention for each core is: Field-Activity_Core-ID_[LASR]_[XZ or YZ slice]_R.jpg. Location information for each sediment core can be found in the 2021_612_2020_625_2020_615_core_nav shapefile included in this data release. Entity_and_Attribute_Detail_Citation: U.S. Geological Survey Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey - CMGDS Contact_Address: Address_Type: mailing and physical Address: 2885 Mission Street City: Santa Cruz State_or_Province: CA Postal_Code: 95060 Contact_Voice_Telephone: 831-427-4747 Contact_Electronic_Mail_Address: pcmsc_data@usgs.gov Resource_Description: Core CT images are provided in a zip archive (2021-612_2020-625_2020-615_core_CT_Images.zip) accompanied by CSDGM FGDC-compliant metadata. Note that rulers appended to images are provided for scale only and do not necessarily correlate with length measurements in the tabular data provided with this data release (for example the length along a core where a radiocarbon sample was collected). Users are advised to use the rulers as a scale to make length measurements along the core. Full 3D CT scan volumes are available upon request; please contact the PCMSC Data Coordinator about availability. Distribution_Liability: 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. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: JPEG Format_Version_Number: NA Format_Information_Content: Zip file contains CT scans of each core in JPG format. File_Decompression_Technique: Zip files may be decompressed with any zip utility (for example, 7zip, WinZip, Archive Utility). Transfer_Size: 283.6 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://doi.org/10.5066/P924775B Access_Instructions: Data can be downloaded using the Network_Resource_Name link and scrolling to the Imagery Data section. Fees: None. Technical_Prerequisites: Core photographs can be viewed with any standard image software. Metadata_Reference_Information: Metadata_Date: 20230706 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey, Pacific Coastal and Marine Science Center Contact_Person: PCMSC Science Data Coordinator Contact_Address: Address_Type: mailing and physical Address: 2885 Mission Street City: Santa Cruz State_or_Province: CA Postal_Code: 95060 Contact_Voice_Telephone: 831-427-4747 Contact_Electronic_Mail_Address: pcmsc_data@usgs.gov Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998