Landslide mass-wasting zones offshore of Southern California, 2023

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Frequently anticipated questions:

What does this data set describe?

Title:
Landslide mass-wasting zones offshore of Southern California, 2023
Abstract:
Landslide mass-wasting zones 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 mass-wasting zones 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 landslides 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: -121.542615
    East_Bounding_Coordinate: -117.605206
    North_Bounding_Coordinate: 34.388852
    South_Bounding_Coordinate: 31.220786
  3. What does it look like?
    masswastingzones_offshore_socal_2023_thumb.png (PNG)
    Southern California location map with bathymetry and mass wasting/slide zones
  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: polygon 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):
      • GT-polygon composed of chains (36)
    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.
  7. How does the data set describe geographic features?
    slidezones_offshore_socal_2023
    polygons representing mapped mass-wasting zones (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
    name_id
    the name of the mass-wasting zone (Source: U.S. Geological Survey and California Geological Survey) Mass-wasting zone names are a unique shortform abbreviated name based on mass-wasting zone location. We define prefixes as follows: 30mile is Thirtymile Bank; 40mile is Fortymile Bank; CB is Catalina Basin; CI is Catalina Island; CR is Cortez Ridge; GSC is Gulf of Santa Catalina; PE is Patton Escarpment; SBB is Santa Barbara Basin; SCB is Santa Cruz Basin; SCCR is Santa Cruz-Catalina Ridge; SMB is Santa Monica Basin; SPB is San Pedro Basin. Names are prepended with “zone” and are appended with unique whole number identifiers.
    location
    the geographic location of the mass-wasting zone (Source: U.S. Geological Survey and California Geological Survey) The geographic location of the mass-wasting zone
    area_m2
    Area of mass-wasting zone in square meters (Source: Esri)
    Range of values
    Minimum:138488
    Maximum:1353691751
    Units:square meters
    Resolution:1
    area_err
    Estimated mass-wasting zone area uncertainty from data resolution and user interpretation, values in square meters. GIS-calculated area was approximated as a circle geometry with radius uncertainty of plus or minus 50 meters and plus or minus 20 meters for areas greater and less than 100,000 square meters, respectively. These values are based on 2 pixels of the likely resolution of bathymetric data used for mapping (25-meter and 10-meter resolutions). The calculated error is the standard deviation of the maximum, minimum, and picked geometries. (Source: U.S. Geological Survey)
    Range of values
    Minimum:66116
    Maximum:6521311
    Units:square meters
    Resolution:1
    slope_deg
    GIS-calculated mean slope approximation of the mass-wasting zone in degrees from the underlying NCEI Coastal Relief Model gridded slope map (Source: U.S. Geological Survey and California Geological Survey)
    Range of values
    Minimum:4.7
    Maximum:25
    Units:degrees
    Resolution:0.1
    sed_age
    geologic age of sediment for the majority of the failure area, from literature, "unspecified" if no age data are 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 a comprehensive list of sources used (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
    Pliocenean age of 5.33-2.59 Ma
    Quaternaryan age of 2.58 Ma-Present
    sedage_ref
    citation information for the sed_age attribute, "n/a" if no age data are available (Source: U.S. Geological Survey and California Geological Survey) Source citations used to characterize the age of the failed 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:
    Polygon shapefile containing outlines and attributes of mass-wasting zones 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 mass-wasting zones 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.
    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
    • NOAA 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 attribute.
  2. How accurate are the geographic locations?
    These data and associated attributes have been created from several bathymetric datasets. Mass-wasting zone mapping was cross-checked where more than one bathymetric dataset spanned a suspected mass-wasting zone. The accuracy of mass-wasting zone mapping correlates to the highest resolution dataset that spans a particular mass-wasting zone.
  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? masswastingzones_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)
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