Landslide scarps offshore of Southern California, 2023

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Frequently anticipated questions:

What does this data set describe?

Title: Landslide scarps offshore of Southern California, 2023
Abstract:
Landslide scarp features have been mapped offshore of Southern California. Polygons were mapped from visual interpretation of high-resolution multibeam echosounder data (MBES) and single-beam echosounder data.
Supplemental_Information:
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?
    Papesh, Antoinette G., Walton, Maureen L., Conrad, James E., Brothers, Daniel S., Kluesner, Jared W., and McGann, Mary L., 20230821, Landslide scarps offshore of Southern California, 2023: data release DOI:10.5066/P9IIWTYL, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

    Online Links:

    This is part of the following larger work.

    Papesh, Antoinette G., Walton, Maureen L., Conrad, James E., Brothers, Daniel S., Kluesner, Jared W., and McGann, Mary L., 2023, Digital maps of submarine landslide and mass wasting features offshore of southern California, 2023: data release DOI:10.5066/P9IIWTYL, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -121.392694
    East_Bounding_Coordinate: -117.310185
    North_Bounding_Coordinate: 34.808265
    South_Bounding_Coordinate: 32.425737
  3. What does it look like?
    scarps_offshore_socal_2023_thumb.png (PNG)
    Southern California location map with bathymetry and mapped scarps
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 1998
    Ending_Date: 30-Jul-2021
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: polyline shapefile
  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):
      • string (1456)
    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 0.0001. Longitudes are given to the nearest 0.0001. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is D_WGS_1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257223563.
      Vertical_Coordinate_System_Definition:
      Depth_System_Definition:
      Depth_Datum_Name: North American Vertical Datum of 1988
      Depth_Resolution: 1.0
      Depth_Distance_Units: meters
      Depth_Encoding_Method: Explicit depth coordinate included with horizontal coordinates
  7. How does the data set describe geographic features?
    scarps_offshore_socal_2023
    polylines representing mapped scarps (Source: U.S. Geological Survey)
    FID
    internal feature number (Source: Esri) automatically generated sequential unique whole number identifier
    Shape
    feature geometry (Source: Esri) feature type
    location
    the geographic location of the scarp (Source: U.S. Geological Survey and California Geological Survey) The commonly reported geographic location of the scarp
    scrp_len_m
    GIS-calculated length of the feature in meters (Source: Esri)
    Range of values
    Minimum:19
    Maximum:27240
    Units:meters
    Resolution:1
    dep_min_m
    GIS-calculated value of the minimum depth along the scarp from the NCEI coastal relief model (NOAA National Geophysical Data Center, 2003); values in meters (Source: Esri)
    Range of values
    Minimum:0
    Maximum:3554
    Units:meters
    Resolution:1
    dep_max_m
    GIS-calculated value of the maximum depth along the scarp from the NCEI coastal relief model (NOAA National Geophysical Data Center, 2003); values in meters (Source: Esri)
    Range of values
    Minimum:5
    Maximum:3584
    Units:meters
    Resolution:1
    prox_coast
    GIS calculated value of the distance in meters between the scarp and the coastline from the NCEI coastal relief model (NOAA National Geophysical Data Center, 2003) (Source: Esri)
    Range of values
    Minimum:0
    Maximum:95768
    Units:meters
    Resolution:1
    prox_130m
    GIS calculated value of the distance in meters between the scarp and the 130 meter depth contour created from the NCEI coastal relief model (NOAA National Geophysical Data Center, 2003) (Source: Esri)
    Range of values
    Minimum:0
    Maximum:86703
    Units:meters
    Resolution:1
    prox_qflts
    GIS calculated value of the distance in meters between the scarp and to faults in the Quaternary Faults Offshore of California compilation by Walton et al., 2020 (Source: Esri)
    Range of values
    Minimum:0
    Maximum:91028
    Units:meters
    Resolution:1
    sed_age
    geologic age of sediment for the majority of the failure area, from literature, “unspecified” if no age determination available. See the sedage_ref attribute and the accompanying ReferencesCited_offshore_socal_2023.pdf file in the Attached Files section (https://www.sciencebase.gov/catalog/item/5d9bc778e4b0366162923190), for details on where to find accuracy information regarding the data reported in the sed_age attribute. (Source: U.S. Geological Survey)
    ValueDefinition
    pre-Late Cretaceousan age older than 99.6 Ma
    Paleocenean age of 55.8-65.5 Ma
    Eocenean age of 55.8-33.9 Ma
    Miocenean age of 23.03-5.33 Ma
    Late Miocenean age of 11.63-5.33 Ma
    Pliocenean age of 5.33-2.59 Ma
    Quaternaryan age of 2.58 Ma-Present
    Pleistocenean age of 2.58 Ma-11.7 ka
    late Pleistocenean age of 129.0-11.7 ka
    Holocenean age of 11.7 ka-Present
    sedage_ref
    citation information for the sed_age attribute (Source: U.S. Geological Survey and California Geological Survey) Source citations used to characterize the age of the sediment in the sed_age attribute. See the accompanying ReferencesCited_offshore_socal_2023.pdf file in the Attached Files section (https://www.sciencebase.gov/catalog/item/5d9bc778e4b0366162923190), for a comprehensive list of sources used.
    Entity_and_Attribute_Overview:
    Polyline shapefile containing shapes of scarp features offshore of California.
    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)
    • Antoinette G. Papesh
    • Maureen L. Walton
    • James E. Conrad
    • Daniel S. Brothers
    • Jared W. Kluesner
    • Mary L. McGann
  2. Who also contributed to the data set?
  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?

These data were compiled as a part of a USGS effort to understand the geologic processes of mass wasting offshore of Southern California. They are intended to provide baseline knowledge of the geology, geomorphology, and distribution of scarps offshore of Southern California, for use by scientists, managers, and the general public. The data can be used with geographic information systems (GIS) software for research purposes.

How was the data set created?

  1. From what previous works were the data drawn?
    Dartnell and others, 2015 (source 1 of 5)
    Dartnell, Peter, Driscoll, Neal W., Brothers, Daniel S., Conrad, James E., Kluesner, Jared, Kent, Graham, and Andrews, Brian D., 2015, Colored shaded-relief bathymetry, acoustic backscatter, and selected perspective views of the inner continental borderland, southern California: Scientific Investigations Map DOI:10.3133/sim3324, U.S. Geological Survey, Reston, VA.

    Online Links:

    Type_of_Source_Media: Digital Resource
    Source_Contribution:
    High resolution multibeam bathymetry was used as a base layer to begin drawing polygons for landslide interpretation. This source is a compilation of new and publicly available multibeam bathymetry data gridded at 25-meter resolution. Links to the data sources used are in the Data Catalog of the report.
    Dartnell and others, 2021 (source 2 of 5)
    Dartnell, Peter, Roland, Emily C., Raineault, Nicole A., Castillo, Christopher M., Conrad, James E., Kane, Renato, Brothers, Daniel S., Kluesner, Jared W., and Maureen A. L. Walton, 2021, Colored shaded-relief bathymetry, acoustic backscatter, and selected perspective views of the northern part of the California Continental Borderland, southern California: Scientific Investigations Map DOI:10.3133/sim3473, U.S. Geological Survey, Reston, VA.

    Online Links:

    Type_of_Source_Media: Digital resource
    Source_Contribution:
    High resolution multibeam bathymetry was used as a base layer to begin drawing polygons for landslide interpretation. This is a compilation of publicly available multibeam bathymetry data published at various resolutions ranging from 2-30 meters. Data sources used are shown on Figure 1 of the report and links to the data are provided therein.
    Seafloor Mapping Lab, 2018 (source 3 of 5)
    Seafloor Mapping Lab of California State University Monterey Bay, 2018, California Margin Geology Series: California State University, Monterey Bay, Seaside, CA.

    Online Links:

    Type_of_Source_Media: Digital resource
    Source_Contribution:
    High resolution multibeam bathymetry was used as a base layer to begin drawing polygons for landslide interpretation. High resolution multibeam bathymetry data at resolutions ranging from 2 – 10 meters from survey datasets H11875, H11876, H11877, H11878, H11879, H11880, H11881, H11882, H11883, H11891, H11950, H11951, H11952, H11953, and the 2014 Southern California Data Gap Project (Dana Point, San Onofre Blocks 01-03, La Jolla, Mission Beach, Point Loma North, Point Loma South, and Imperial Beach) were used.
    MBARI Seafloor Mapping Team, 2001 (source 4 of 5)
    Mapping, MBARI Seafloor Team, 2001, Santa Barbara multibeam survey: MBARI, online.

    Online Links:

    Type_of_Source_Media: Digital resource
    Source_Contribution:
    High resolution multibeam bathymetry was used as a base layer to begin drawing polygons for landslide interpretation. This is 20-meter resolution bathymetry data.
    National Geophysical Data Center, 2012 (source 5 of 5)
    NOAA, 2012, U.S. Coastal Relief Model - Southern California vers. 2: NOAA, online.

    Online Links:

    Type_of_Source_Media: Digital resource
    Source_Contribution:
    The NCEI 3-arc-second elevation grid (approximately 90-meter resolution) was used as a base layer to begin drawing polygons for landslide interpretation where no high resolution multibeam bathymetry data (listed above) were available.
  2. How were the data generated, processed, and modified?
    Date: 02-Feb-2023 (process 1 of 1)
    A compilation of existing bathymetry data was used as a base layer to map landslide features. Data from listed sources was downsampled in ESRI ArcMap and merged into a single 30-m grid to create the base layer. In some cases, the source swath data was higher resolution than the 30-m compilation and was used to map landslide features. A list of source swath data is detailed in the Source Used Citations. Where high (<30 m) resolution data was unavailable, the 90-m resolution NOAA Coastal Relief Model was used as the base layer. Using this base layer, landslides, headwall scarps, and areas of mass-wasting were mapped. Mapped landslide bodies were divided into evacuation zones and debris aprons based on negative (i.e., evacuation zones) or positive (i.e., debris aprons) seafloor relief associated with the landslide masses. Data sources used in this process:
    • Dartnell and others, 2015
    • Dartnell and others, 2021
    • Seafloor Mapping Lab, 2018
    • MBARI Seafloor Mapping Team, 2001
    • National Geophysical Data Center, 2012
  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?
    No formal attribute accuracy tests were conducted. See the sedage_ref attribute within the shapefile, and the accompanying ReferencesCited_offshore_socal_2023.pdf file in the Attached Files section (https://www.sciencebase.gov/catalog/item/5d9bc778e4b0366162923190), for details on where to find accuracy information regarding the data reported in the sed_age and attribute.
  2. How accurate are the geographic locations?
    These data and associated attributes have been created from several. Scarp mapping was cross-checked where more than one bathymetric dataset spanned a suspected scarp. The accuracy of scarp mapping correlates to the highest resolution dataset that spans a particular scarp.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    Dataset is considered complete for the information presented, as described in the abstract.
  5. How consistent are the relationships among the observations, including topology?
    No formal logical accuracy 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 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 - ScienceBase
    Denver Federal Center, Building 810, Mail Stop 302
    Denver, CO

    1-888-275-8747 (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? scarps_offshore_socal_2023.zip contains the shapefile and associated files, and is accompanied by a browse image and 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?
  5. What hardware or software do I need in order to use the data set?
    These data can be viewed with GIS software.

Who wrote the metadata?

Dates:
Last modified: 21-Aug-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/ScienceBase/DR_P9IIWTYL/scarps_offshore_socal_2023_metadata.faq.html>
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