Folds--Offshore of Ventura, California

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What does this data set describe?

Title: Folds--Offshore of Ventura, California
This part of SIM 3254 presents data for folds for the geologic and geomorphic map (see sheet 10, SIM 3254) of the Offshore of Ventura map area, California. The vector data file is included in "," which is accessible from <>.
The Offshore of Ventura map area is in the Ventura Basin, in the southern part of the Western Transverse Ranges geologic province, which is north of the California Continental Borderland (Fisher and others, 2009). This province has undergone significant north-south compression since the Miocene, and recent GPS data suggest north-south shortening of about 6 to 10 mm/yr (Larson and Webb, 1992; Donnellan and others, 1993). The active, north-verging Oak Ridge Fault and the south-verging Pitas Point-Ventura Fault are two of the structures on which this shortening occurs (for example, Sorlien and others, 2000; Fisher and others, 2005, 2009). High-resolution seismic-reflection profiles (sheet 8, SIM 3254) reveal that neither fault ruptures the surface; instead, the surface expression of each fault is a narrow, asymmetric fold that involves the uppermost Pleistocene and Holocene (less than 21 ka) sedimentary section. Both structures are inferred to be parts of long fault systems that extend for more than 100 km, representing important potential earthquake hazards (for example, Fisher and others, 2009). Shortening is also occurring on the Montalvo Fault and Anticline system along the southeast edge of the map area (part of the broader Oak Ridge Fault Zone; Yeats, 1998) and on the Rincon-Ventura Avenue Anticline (for example, Rockwell and others, 1988), which crosses the northwest edge of the map area.
References Cited
Donnellan, A., Hager, B.H., and King, R.W., 1993, Discrepancy between geologic and geodetic deformation rates in the Ventura basin: Nature, v. 346, p. 333?336.
Fisher, M.A., Greene, H.G., Normark, W.R., and Sliter, R.W., 2005, Neotectonics of the offshore Oak Ridge fault near Ventura, southern California: Bulletin of the Seismological Society of America, v. 95, p. 739?744.
Fisher, M.A., Sorlien, C.C., and Sliter, R.W., 2009, Potential earthquake faults offshore southern California from the eastern Santa Barbara channel to Dana Point, in Lee, H.J., and Normark, W.R., eds., Earth science in the urban ocean--The Southern California Continental Borderland: Geological Society of America Special Paper 454, p. 271-290.
Larson, K.M., and Webb, F.H., 1992, Deformation in the Santa Barbara Channel from GPS measurements 1987-1991: Geophysical News Letters, v. 19, p. 1,491-1,494.
Rockwell, T.K., Keller, E.A., and Dembroff, G.R., 1988, Quaternary rate of folding of the Ventura Avenue anticline, western Transverse Ranges, southern California: Geological Society of America Bulletin, v. 100, p. 850-858.
Sorlien, C.C., Gratier, J.P., Luyendyk, B.P., Hornafius, J.S., and Hopps, T.E, 2000, Map restoration of folded and faulted late Cenozoic strata across the Oak Ridge fault, onshore and offshore Ventura basin, California: Geological Society of America Bulletin, v. 112, p. 1,080-1,090.
Yeats, R.S., 1998, North-vergent thick-skinned or south-vergent thin-skinned Oak Ridge fault--A view from the coast, in Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., eds., Structure and petroleum geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, Pacific Section and Coast Geological Society, Miscellaneous Publication 46, p. 143-152.
Map political location: Ventura County, California Compilation scale: 1:24,000 Base maps used are hillshades generated from IfSAR, LiDAR, and multibeam mapping both onshore and offshore (see sheet 2, SIM 3254, for more information).
  1. How should this data set be cited?

    Ritchie, A.C., and Johnson, S.Y., 2013, Folds--Offshore of Ventura, California:.

    This is part of the following larger work.

    Johnson, Samuel Y. , Dartnell, Peter, Cochrane, Guy R. , Golden, Nadine E. , Phillips, Eleyne L. , Ritchie, Andrew C. , Kvitek, Rikk G. , Greene, H. Gary , Krigsman, Lisa M. , Endris, Charles A. , Seitz, Gordon G. , Gutierrez, Carlos I. , Sliter, Ray W. , Erdey, Mercedes D. , Wong, Florence L. , Yoklavich, Mary M. , Draut, Amy E. , Hart, Patrick E. , and Cochran, Susan A. , 2013, California State Waters Map Series--Offshore of Ventura, California: Scientific Investigations Map SIM 3254, U.S. Geological Survey, Reston, VA.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -119.4481
    East_Bounding_Coordinate: -119.2494
    North_Bounding_Coordinate: 34.3761
    South_Bounding_Coordinate: 34.2187

  3. What does it look like?

  4. Does the data set describe conditions during a particular time period?

    Calendar_Date: 2013
    Currentness_Reference: Publication Date

  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):

      • String (8)

    2. What coordinate system is used to represent geographic features?

      The map projection used is WGS 1984 UTM Zone 11N.

      Projection parameters:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -117.0
      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?

    lines representing mapped folds (Source: This report)

    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    feature label (Source: this report)

    text field containing feature names if they are named

    Representation rule identifier (Source: This report)

    This field contains the representation rule in the ArcGIS file geodatabase that applied dashed or solid lines to folds. The line is dashed if folds are mapped in sediment and solid if they are mapped over rock or a visible scarp.

    Length of feature in internal units. (Source: ESRI)

    Positive real numbers that are automatically generated.

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

  3. To whom should users address questions about the data?

    USGS Pacific Coastal and Marine Science Center
    c/o Stephen Hartwell
    400 Natural Bridges Drive
    Santa Cruz, CA 95060

    (831) 460-7814 (voice)
    (831) 427-4748 (FAX)

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 Santa Barbara coastal plain 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?

    Sliter and others, 2008 (source 1 of 1)
    Ray W. Sliter, Peter J. Triezenberg, Patrick E. Hart, 2008, High-resolution chirp and mini-sparker seismic-reflection data from the southern California continental shelf--Gaviota to Mugu Canyon: U.S. Geological Survey Open-File Report 2008-1246, U.S. Geological Survey, Menlo Park, CA.

    Online Links:

    seismic data files (.sgy files) ASCII lat/long shot point files TIFF images of processed seismic lines
    Digital seismic data used to interpret subsurface geologic structure

  2. How were the data generated, processed, and modified?

    Date: 2010 (process 1 of 1)
    Folds were mapped onto shot lines based on the latitude and longitude of seismic picks from Sliter and others (2008).

  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?

  2. How accurate are the geographic locations?

    Folds were primarily mapped by interpretation of seismic reflection profile data (see sheet 8, SIM 3254).
    Folds lines were digitized by heads-up screen digitization on to shot point picks from seismic line navigation data - each shot point has an associated lat/long in the survey data. Error is introduced from layback, as well as from interpretation of oblique features, so horizontal accuracy of fault and fold location is estimated to be on the order of 10 to 20 meters.

  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, 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?

If physical samples or materials are available, constraints on their on-site access are described in "WR CMG Sample Distribution Policy" at URL: <>
This information is not intended for navigational purposes.
Read and fully comprehend the metadata prior to data use. Uses of these data should not violate the spatial resolution of the data. Where these data are used in combination with other data of different resolution, the resolution of the combined output will be limited by the lowest resolution of all the data.
Acknowledge the U.S. Geological Survey in products derived from these data. Share data products developed using these data with the U.S. Geological Survey.
This database has been approved for release and publication by the Director of the USGS. Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use.
Although this Federal Geographic Data Committee-compliant metadata file is intended to document these data in nonproprietary form, as well as in ArcInfo format, this metadata file may include some ArcInfo-specific terminology.

Who wrote the metadata?

Last modified: 2012
Metadata author:
U.S. Geological Survey, Coastal and Marine Geology Program
c/o Stephen R. Hartwell
400 Natural Bridges Drive
Santa Cruz, CA 95060-5792

831-460-7814 (voice)
831-427-4748 (FAX)

Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

Generated by mp version 2.9.6 on Mon Jul 08 16:02:02 2013