Computed tomography (CT) scans of sediment cores collected offshore Cascadia, during field activities 2020-633-FA and 2021-636-FA

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Frequently anticipated questions:

What does this data set describe?

Title:
Computed tomography (CT) scans of sediment cores collected offshore Cascadia, during field activities 2020-633-FA and 2021-636-FA
Abstract:
This dataset includes computed tomography (CT) scan imagery of sediment cores collected along the Cascadia Subduction zone. These cores were collected by the Monterey Bay Aquarium Research Institute (MBARI) aboard the R/V Western Flyer in 2020 and 2021 using the remotely operated vehicle (ROV) Doc Ricketts. All cores were transported to the U.S. Geological Survey's Pacific Coastal and Marine Science Center sediment core laboratory for CT scanning.
Supplemental_Information:
Additional information about the field activity from which these data were derived is available online at:
https://cmgds.marine.usgs.gov/fan_info.php?fan=2020-633-FA https://cmgds.marine.usgs.gov/fan_info.php?fan=2021-636-FA
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
  1. How might this data set be cited?
    Hill, Jenna C., SeanPaul M. La Selle, Paull, Charles K., Gwiazda, Roberto, Lundsten, Eve M., Nieminski, Nora M., McGann, Mary L., Lorenson, Thomas D., Watt, Janet T., Caissie, Beth, and Starratt, Scott W., 20260108, Computed tomography (CT) scans of sediment cores collected offshore Cascadia, during field activities 2020-633-FA and 2021-636-FA: data release DOI:10.5066/P1JUTTAN, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

    This is part of the following larger work.

    Hill, Jenna C., SeanPaul M. La Selle, Paull, Charles K., Gwiazda, Roberto, Lundsten, Eve M., Nieminski, Nora M., McGann, Mary L., Lorenson, Thomas D., Watt, Janet T., Caissie, Beth, and Starratt, Scott W., 2026, Sediment core data from offshore Cascadia during field activities 2020-633-FA and 2021-636-FA: data release DOI:10.5066/P1JUTTAN, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

    Other_Citation_Details:
    Suggested Citation: Hill, J.C, La Selle, S.M., Paull, C.K., Gwiazda, R., Lundsten, E.M., Nieminski, N.M., McGann, M.L., Lorenson, T., Watt, J.T., Caissie, B., and Starratt, S., 2026, Sediment core data from offshore Cascadia during field activities 2020-633-FA and 2021-636-FA: U.S. Geological Survey data release, https://doi.org/10.5066/P1JUTTAN.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -125.22413
    East_Bounding_Coordinate: -125.17323
    North_Bounding_Coordinate: 41.71185
    South_Bounding_Coordinate: 41.70170
  3. What does it look like?
    VC874_01_ct_preview.jpg (JPG)
    Example CT image of a section of core VC874, section 01.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 09-Sep-2020
    Ending_Date: 31-Aug-2021
    Currentness_Reference:
    Ground conditions at time data were collected
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: raster digital data
  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 (56)
    2. What coordinate system is used to represent geographic features?
      Vertical_Coordinate_System_Definition:
      Depth_System_Definition:
      Depth_Datum_Name: Local surface
      Depth_Resolution: 0.1
      Depth_Distance_Units: centimeters
      Depth_Encoding_Method: Attribute values
  7. How does the data set describe geographic features?
    2020-633-FA_2021-636-FA_core_ct.zip
    A zip file containing 56 TIFF files of CT images and their respective software-proprietary XML files. Two TIFF files containing downcore CT images of coronal (XZ) and saggital (YZ) views are provided for each scanned core section. (Source: Producer defined)
    orthogonal CT image metadata XML file
    This Geotek software-proprietary XML file contains information on CT scan acquisition settings and reconstruction settings. The following attributes and example attribute values are provided: <geotek-image> <image-type>giCTOrthogonalView</image-type> <coreID>VC874</coreID> <section-number>01</section-number> <physical-width>8.95</physical-width> <physical-height>150.27</physical-height> <physical-top>0.01</physical-top> <pixels-per-CM>105</pixels-per-CM> <horizontal-resolution>105</horizontal-resolution> <pixel-width>940</pixel-width> <scan-lines>15719</scan-lines> <comments> Enter Comments Here</comments> <camera-name>Thermo Kevex PSX10-65W</camera-name> <average-of>1</average-of> <filename>2020_633_DR1282_VC874_01_XZView.TIF</filename> <x-ray-voltage>110</x-ray-voltage> <x-ray-current>275.3</x-ray-current> <x-ray-spot-size>42</x-ray-spot-size> <source-object-distance>224.73</source-object-distance> <source-detector-distance>585.01</source-detector-distance> <detector-CCD-mode>2x2</detector-CCD-mode> <image-enhancement-filter>Enabled=False,WindowCount=2,Window=400,SigmaA=0.1,SigmaV=0.0005,Weight=0.4,Window=100,SigmaA=0.1,SigmaV=0.0005,Weight=1,Reduction=0.85</image-enhancement-filter> <is-a-sync-scan-image>0</is-a-sync-scan-image> </geotek-image> (Source: producer defined) These Geotek software-proprietary XML files contain information on CT scan acquisition settings and image scaling information. The values in the example provided may be different for each scan. Please contact the PCMSC data coordinator for more information on the contents of these XML files.

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Jenna C. Hill
    • SeanPaul M. La Selle
    • Charles K. Paull
    • Roberto Gwiazda
    • Eve M. Lundsten
    • Nora M. Nieminski
    • Mary L. McGann
    • Thomas D. Lorenson
    • Janet T. Watt
    • Beth Caissie
    • Scott W. Starratt
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    PCMSC Science Data Coordinator
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    2885 Mission Street
    Santa Cruz, CA

    831-427-474 (voice)
    pcmsc_data@usgs.gov

Why was the data set created?

As part of a multi-year project focused on characterizing offshore marine geohazards (tsunamis, earthquakes, and landslides), the U.S. Geological Survey (USGS) Coastal and Marine Hazards and Resources Program is conducting research offshore northern California, Oregon, and Washington to gain a better understanding of the geologic hazards of the region, improve risk assessments for local communities and critical infrastructure, and to provide data for future research on regional tectonic, sedimentary, and geomorphic evolution. Sediment cores were collected to enable a detailed investigation of Cascadia's geologic history and ongoing activity.

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: 2022 (process 1 of 1)
    CT scans were acquired at the USGS Pacific Coastal and Marine Science Center core facility using a Geotek Rotating X-Ray CT (RXCT) Scanner system, running acquisition software version XCT4. Rotational x-ray images were acquired with a Thermo Kevex PSX10-65W x-ray source every 0.2 degrees at 110 kilovolts (kV) and 270 microamperes. Core segments were scanned individually. Rotational images were reconstructed into axial slice TIFFs using Geotek's Reconstructor Software. Once reconstructed, the axial slice TIFFs were imported into GeoTek's Image Viewer software and representative two-dimensional orthogonal views were selected from the coronal (XZ) and saggital (YZ) planes. A ruler was added to the orthogonal TIFF images using the GeoTek Add Ruler v1.4 software and represents in-section depth in centimeters. TIFFs are provided in 16-bit unsigned integer, single channel format. File names correspond to the names of each core segment. For example '2021_636_VC1031_01_XZView.tif' corresponds to the coronal view of the first segment of the vibracore 'VC1031'. A list of orthogonal CT TIFF images is included in this data release in the 2020-633-FA_2021-636-FA_cores.csv file.
  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. No formal attribute accuracy tests were conducted.
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
    Core depth values are relative to the top of sediment in the uppermost core section. Coring-induced compaction, if any, was not determined. No formal vertical accuracy tests were conducted.
  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.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints No access constraints. Please see 'Distribution Info' for details.
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. These data are marked with a Creative Common CC0 1.0 Universal License. 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? CT images are provided in a zip archive (2020-633-FA_2021-636-FA_cores_ct.zip) with CSDGM FGDC compliant metadata. Please contact the PCMSC Data Coordinator about availability.
  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 CT core imagery in TIFF format and associated proprietary metadata in XML format. in format TIFF, XML (version Geotek RXCT Scanner system, software version XCT4) Size: 1130
      Network links: https://doi.org/10.5066/P1JUTTAN
    • Cost to order the data: None.

  5. What hardware or software do I need in order to use the data set?
    CT images can be viewed with any standard image software. Proprietary metadata XML files can be viewed with any standard text editing software.

Who wrote the metadata?

Dates:
Last modified: 08-Jan-2026
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_P1JUTTAN/2020-633-FA_2021-633-FA_cores_ct_metadata.faq.html>
Generated by mp version 2.9.51 on Fri Jan 16 11:53:35 2026