Geology and geomorphology--Offshore of Aptos Map Area, California

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Frequently anticipated questions:


What does this data set describe?

Title:
Geology and geomorphology--Offshore of Aptos Map Area, California
Abstract:
This part of DS 781 presents data for the geologic and geomorphic map of the Offshore Aptos map area, California. The vector data file is included in "Geology_OffshoreAptos.zip," which is accessible from https://doi.org/10.5066/F7K35RQB. These data accompany the pamphlet and map sheets of Cochrane, G.R., Johnson, S.Y., Dartnell, P., Greene, H.G., Erdey, M.D, Dieter, B.E., Golden, N.E., Hartwell, S.R., Ritchie, A.C., Kvitek, r.G., Maier, K.L., Endris, C.A., Davenport, C.W., Watt, J.T., Sliter, R.W., Finlayson, D.P., and Krigsman, L.M., (G.R. Cochrane and S.A. Cochran, eds.), 2016, California State Waters Map Series—Offshore of Aptos, California: U.S. Geological Survey Open-File Report 2016–1025, 43 p., 10 sheets, scale 1:24,000, https://doi.org/10.3133/ofr20161025.
Marine geology and geomorphology were mapped in the Offshore of Aptos map area, California, from approximate Mean High Water (MHW) to the 3-nautical-mile limit of California''s State Waters. Offshore geologic units were delineated on the basis of integrated analyses of adjacent onshore geology with multibeam bathymetry and backscatter imagery, seafloor-sediment and rock samples, digital camera and video imagery, and high-resolution seismic-reflection profiles.
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=S709MB https://cmgds.marine.usgs.gov/fan_info.php?fan=S1009MB https://cmgds.marine.usgs.gov/fan_info.php?fan=SN109MB https://cmgds.marine.usgs.gov/fan_info.php?fan=W3482MB
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?
    Johnson, Samuel Y., Hartwell, Stephen R., Davenport, Clifton W., and Maier, Katie L., 2015, Geology and geomorphology--Offshore of Aptos Map Area, California: Data Series DS 781, U.S. Geological Survey, Reston, VA.

    Online Links:

    This is part of the following larger work.

    Golden, Nadine E., 2015, California State Waters Map Series Data Catalog: Data Series DS 781, U.S. Geological Survey, Reston, VA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -122.00
    East_Bounding_Coordinate: -121.80
    North_Bounding_Coordinate: 36.98
    South_Bounding_Coordinate: 36.84
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/5576269de4b032353caef2b1?f=__disk__91%2F3c%2Fd5%2F913cd56190b0dce14c6b07f3d51414c050260034&allowOpen=true (JPEG)
    Geology offshore of Aptos, California.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 1982
    Ending_Date: 2010
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: vector digital data
  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 (822)
    2. What coordinate system is used to represent geographic features?
      The map projection used is WGS 1984 UTM Zone 10N.
      Projection parameters:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -123.0
      Latitude_of_Projection_Origin: 0.0
      False_Easting: 500000.0
      False_Northing: 0.0
      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.0001
      Ordinates (y-coordinates) are specified to the nearest 0.0001
      Planar coordinates are specified in Meter
      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?
    MapUnitPolys
    Polygons representing geologic / geomorphic map units (Source: This report)
    OBJECTID
    Internal feature number. (Source: ESRI) Sequential unique whole numbers that are automatically generated.
    Shape
    Feature geometry. (Source: ESRI) Coordinates defining the features.
    MapUnitAbbrev
    Map Unit abbreviation (Source: This report)
    ValueDefinition
    afArtificial fill
    QmsMarine nearshore and shelf deposits
    QmscCoarse-grained marine nearshore and shelf deposits
    QmsfFine-grained marine shelf deposits
    QmsdMarine shelf scour depressions
    Qms/TpSediment-covered Purisima Formation
    Qmsf/TpSediment-covered Purisima Formation
    QmshMarine shelf hummocky seafloor
    QcwSubmarine canyon wall deposits
    QcfaSubmarine canyon axial channel deposits
    Qwp3Submerged wave-cut platform
    Qwpr3Submerged wave-cut platform riser
    Qwp2Submerged wave-cut platform
    Qwpr2Submerged wave-cut platform riser
    Qwp1Submerged wave-cut platform
    Qwpr1Submerged wave-cut platform riser
    TpPurisima Formation
    MapUnit
    short description of map unit (Source: This report) text description of map unit
    Shape_Length
    Length of feature in internal units. (Source: ESRI) Positive real numbers that are automatically generated.
    Shape_Area
    Area of feature in internal units squared. (Source: ESRI) Positive real numbers that are automatically generated.
    RuleID
    Representation rule identifier (Source: This report) This field contains the representation rule in the ArcGIS file geodatabase which applies a solid color fill of a specified CMYK value to each polygon. Representation rules have the same name as the map unit abbreviation.

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Samuel Y. Johnson
    • Stephen R. Hartwell
    • Clifton W. Davenport
    • Katie L. Maier
  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
    US

    831-427-4747 (voice)
    pcmsc_data@usgs.gov

Why was the data set created?

To expand geologic mapping to the seafloor within the California's State Waters, to update coastal geologic mapping, and to contribute to a uniform regional geologic database. Additionally, to provide a geologic map for the public and geoscience community to aid in assessments and mitigation of geologic hazards in the Monterey Bay and Vicinity region and to provide sufficient geologic information for land-use and land-management decisions both onshore and offshore.

How was the data set created?

  1. From what previous works were the data drawn?
    bathymetry (source 1 of 5)
    Dartnell, Peter, Ritchie, Andrew C., and Finlayson, David P., 2015, Bathymetry--Offshore of Aptos Map Area, California: Data Series DS 781, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    See metadata for "BathymetryA_USGS_OffshoreAptos" and "BathymetryB_CSUMB_OffshoreAptos" in DS 781 for source data and postprocessing/reprocessing information.
    Type_of_Source_Media: digital files of gridded bathymetry data (ArcInfo GRID)
    Source_Contribution:
    Gridded bathymetry data at 2- and 3-meter resolution used to help with geologic and geomorphologic interpretations
    backscatter (source 2 of 5)
    Dartnell, Peter, Ritchie, Andrew C., Finlayson, David P., and Kvitek, Rikk G., 2015, Backscatter--Offshore of Aptos Map Area, California: Data Series DS 781, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    See metadata for "BackscatterA_Swath_OffshoreAptos" and "BackscatterB_EM300_OffshoreAptos" in DS 781 for amplitude source data and postprocessing/reprocessing information.
    Type_of_Source_Media:
    digital file of gridded amplitude (backscatter) data (ArcInfo GRID)
    Source_Contribution:
    Gridded amplitude data at 2- and 5-meter resolution used to help with geologic and geomorphologic interpretations
    seismic (source 3 of 5)
    Sliter, Ray W., Johnson, Samuel Y., Watt, Janet T., Scheirer, Daniel S., and Triezenberg, Peter J., 2013, High-resolution seismic-reflection and marine-magnetic data from Offshore Central California--San Gregorio to Point Sur: Open-File Report 2013-1071, U.S. Geological Survey, Menlo Park, CA.

    Online Links:

    Type_of_Source_Media: ASCII lat/long shot point files
    Source_Contribution:
    Digital seismic data used to interpret subsurface geologic structure
    sediment (source 4 of 5)
    Reid, Jane A., Reid, Jamey M., Jenkins, Chris J., Zimmerman, Mark, Williams, S. Jeffress, and Field, Michael E., 2006, usSEABED—Pacific Coast (California, Oregon, Washington) offshore surficial-sediment data release: Data Series DS 182, U.S. Geological Survey, Menlo Park, CA.

    Online Links:

    Type_of_Source_Media: Esri project files, csv files
    Source_Contribution:
    seafloor sediment and rock samples used to interpret seafloor geology
    imagery (source 5 of 5)
    Golden, Nadine E., and Cochran, Guy R., 2013, California Seafloor Mapping Program video and photograph portal: data release DOI:10.5066/F7J1015K, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

    Online Links:

    Type_of_Source_Media: seafloor video and photographs
    Source_Contribution:
    seafloor video and photographs used to interpret seafloor geology
  2. How were the data generated, processed, and modified?
    Date: 2012 (process 1 of 7)
    Map unit polygons were digitized over underlying base layers developed from multibeam bathymetry and backscatter data. Derivatives such as slope and curvature were generated from source rasters. Interpreted rasters include amplitude, hillshaded bathymetry (using various illumination angles and vertical exaggeration), slope, and curvature. Curvature was decomposed into profile and plan curvature for analysis purposes. Data sources used in this process:
    • bathymetry
    • backscatter
    • seismic
    • sediment
    • imagery
    Date: 2014 (process 2 of 7)
    The mapped area was extended to the shoreline by using digital orthophotos to interpret the region between the inner edge of the multibeam bathymetry and the approximate shoreline. The approximate shoreline is from the NOAA Shoreline Mapping Program accessed at (http://www.ngs.noaa.gov/NSDE/). The resulting boundary was transformed to WGS 84 UTM Zone 10 North in ArcGIS 10 using the NAD83 to WGS84 (ITRF00) transformation algorithm. This boundary was then used to extend and trim both onshore and offshore geology in the print and PDF product. Only data for offshore map units are released digitally in this publication. For onshore geology, see Brabb (1997), and Wagner and others (2002). References Cited: Brabb, E.E., 1997, Geologic map of Santa Cruz County, California—A digital database: U.S. Geological Survey Open-File Report 97–489, scale 1:62,500, available at https://doi.org/10.3133/ofr97489. Wagner, D.L., Greene, H.G., Saucedo, G.J., and Pridmore, C.L., 2002, Geologic map of the Monterey 30' × 60' quadrangle and adjacent areas, California: California Geological Survey Regional Geologic Map Series, scale 1:100,000, available at http://www.quake.ca.gov/gmaps/RGM/monterey/monterey.html.
    Date: 05-Oct-2017 (process 3 of 7)
    Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Alan O. Allwardt
    Contractor -- Information Specialist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7551 (voice)
    831-427-4748 (FAX)
    aallwardt@usgs.gov
    Date: 26-Apr-2018 (process 4 of 7)
    Added keywords from Coastal and Marine Ecological Classification Standard (CMECS) to metadata. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Alan O. Allwardt
    Contractor -- Information Specialist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7551 (voice)
    831-427-4748 (FAX)
    aallwardt@usgs.gov
    Date: 22-Jun-2018 (process 5 of 7)
    Corrected author spelling in Larger Work section Person who carried out this activity:
    Susan A Cochran
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    Geologist
    2885 Mission Street
    Santa Cruz, CA
    USA

    (831) 460-7545 (voice)
    scochran@usgs.gov
    Date: 11-Sep-2020 (process 6 of 7)
    Edits were made to bring the metadata up to current PCMSC standards including standardizing authors' names, adding a doi# link, correcting typos, refining keywords, and using current access and distribution liability statements. Point of Contact and Metadata Contact information sections were changed to static PCMSC contact information. No data were changed. Users are advised to compare the metadata date of this file to any similar file to ensure they are using the most recent version. Person who carried out this activity:
    Susan A Cochran
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    2885 Mission St.
    Santa Cruz, CA
    United States

    831-460-7545 (voice)
    scochran@usgs.gov
    Date: 19-Oct-2020 (process 7 of 7)
    Edited metadata to add keywords section with USGS persistent identifier as theme keyword. No data were changed. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
  3. What similar or related data should the user be aware of?
    Cochrane, Guy R., Johnson, Samuel Y., Dartnell, Peter, Greene, H. Gary, Erdey, Mercedes D., Dieter, Bryan E., Golden, Nadine E., Hartwell, Stephen R., Ritchie, Andrew C., Kvitek, Rikk G., Maier, Katherine L., Endris, Charles A., Davenport, Clifton W., Watt, Janet T., Sliter, Ray W., Finlayson, David P., and Krigsman, Lisa M., 2016, California State Waters Map Series--Offshore of Aptos, California: Open-File Report 2016-1025, U.S. Geological Survey, Reston, VA.

    Online Links:


How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
    Polygons were primarily mapped by one of the following methods: (1) interpretation of 2-meter- and 3-meter-resolution hillshaded bathymetry data from bathymetric lidar and sonar surveys; (2) interpretation of 2-meter- and 5-meter-resolution amplitude (backscatter) data from bathymetric sonar surveys; (3) interpretation of seismic-reflection-profile data. Map Unit contact locations were interpreted typically at a scale of between 1:1,000 and 1:2,000 using the above base data. Bathymetric sonar and lidar data have a horizontal accuracy greater than the resolution of the base data. Map unit contacts were digitized by heads-up screen digitization of line data on 2-meter-resolution DEMs described above. Horizontal accuracy is estimated to be between 2 and 5 meters depending on how clearly contacts can be resolved. Most digitized positions on the map are estimated to have better than 5 m horizontal accuracy. There is no elevation data in the polygon shapefile.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    Data are complete: no offshore features that could be accurately identified and represented at the compilation scale of 1:24,000 were eliminated or generalized. The smallest area represented is approximately 100 square meters. All geospatial database elements are attributed.
  5. How consistent are the relationships among the observations, including topology?
    Map elements were visually checked for overshoots, undershoots, duplicate features, polygon closure, and other errors by the lead authors and by the GIS technician(s) who created the digital database. Review drafts of the map were reviewed internally by at least two other geologists for consistency with basic geologic principles and general conformity to USGS mapping standards.

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. This information is not intended for navigation purposes.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey
    345 Middlefield Rd
    Menlo Park, CA
    USA

    (650) 329-4309 (voice)
  2. What's the catalog number I need to order this data set? The download includes the shapefile (.shp) and associated files. The TXT, XML, HTML, and FAQ versions of the metadata for the Geology and Geomorphology data layer of Offshore of Aptos, California are also included in the download.
  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?
    The downloadable data file has been compressed with the "zip" command and can be unzipped with Winzip (or other tool) on Windows systems. To utilize these data, the user must have software capable of uncompressing the WinZip file and importing and viewing an Esri ArcMap TIFF. Users should download the ArcGIS Project File, OffshoreAptosGIS.mxd.zip, a compressed (with the "zip" command) version of the ArcMap document (.mxd) that has all the data layers loaded in the table of contents for "Offshore Aptos" and has all the data symbolized as on the SIM map sheets. Download and save this ArcGIS project file, including all data layers, to the directory the user has created for this G

Who wrote the metadata?

Dates:
Last modified: 19-Oct-2020
Metadata author:
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Attn: PCMSC Science Data Coordinator
2885 Mission Street
Santa Cruz, CA
US

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/SeriesReports/DS_DDS/DS_781/XMLs_on_ScienceBase/F7K35RQB_OffshoreAptos/Geology_OffshoreAptos_metadata.faq.html>
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