H.G. Greene
S.R. Hartwell
M.W. Manson
S.Y. Johnson
B.E. Dieter
E.L. Phillips
J.T. Watt
2014
Folds--Offshore of Pacifica map area, California
vector digital data
Brian D. Edwards
Eleyne L. Phillips
Peter Dartnell
H. Gary Greene
Carrie K. Bretz
Rikk G. Kvitek
Stephen R. Hartwell
Samuel Y. Johnson
Guy R. Cochrane
Brian E. Dieter
Ray W. Sliter
Stephanie L. Ross
Nadine E. Golden
Janet T. Watt
John L. Chin
Mercedes D. Erdey
Lisa M. Krigsman
Michael W. Mansion
Charles A. Endris
2014
California State Waters Map Series--Offshore of Pacifica map area, California
map
Open-File Report
OFR 2014-1260
Reston, VA
U.S. Geological Survey
https://pubs.usgs.gov/of/2014/1260/
Nadine E. Golden
2013
California State Waters Map Series Data Catalog
database
Data Series
DS 781
Reston, VA
U.S. Geological Survey
https://pubs.usgs.gov/ds/781/
This part of DS 781 presents data for folds for the geologic and geomorphic map of the Offshore of Pacifica map area, California. The vector data file is included in "Folds_OffshorePacifica.zip," which is accessible from https://pubs.usgs.gov/ds/781/OffshorePacifica/data_catalog_OffshorePacifica.html.
The Offshore of Pacifica map area straddles the right-lateral transform boundary between the North American and Pacific plates and is cut by several active faults that cumulatively form a distributed shear zone, including the San Andreas Fault, the eastern strand of the San Gregorio Fault, the Golden Gate Fault, and the Potato Patch Fault (sheets 8, 9; Bruns and others, 2002; Ryan and others, 2008). These faults are covered by Holocene sediments (mostly units Qms, Qmsb, Qmst) with no seafloor expression, and are mapped using seismic-reflection data (sheet 8). The San Andreas Fault is the primary plate-boundary structure and extends northwest across the map area; it intersects the shoreline 10 km north of the map area at Pacifica Lagoon, and 3 km south of the map area at Mussel Rock. This section of the San Andreas Fault has an estimated slip rate of 17 to 24 mm/yr (U.S. Geological Survey, 2010), and the devastating Great 1906 California earthquake (M 7.8) is thought to have nucleated on the San Andreas a few kilometers offshore of San Francisco within the map area (sheet 9; Bolt, 1968; Lomax, 2005).
The San Andreas Fault forms the boundary between two distinct basement terranes, Upper Jurassic to Lower Cretaceous rocks of the Franciscan Complex to the east, and Late Cretaceous granitic and older metamorphic rocks of the Salinian block to the west. Franciscan Complex rocks (unit KJf, undivided) form seafloor outcrops at and north of Point Lobos adjacent to onland exposures. The Franciscan is divided into 13 different units for the onshore portion of this geologic map based on different lithologies and ages, but the unit cannot be similarly divided in the offshore because of a lack of direct observation and (or) sampling.
Folds were primarily mapped by interpretation of seismic reflection profile data (see S-15-10-NC and F-2-07-NC). The seismic reflection profiles were collected between 2007 and 2010.
References Cited
Bolt, B.A., 1968, The focus of the 1906 California earthquake: Bulletin of the Seismological Society of America, v. 58, p. 457-471.
Bruns, T.R., Cooper, A.K., Carlson, P.R., and McCulloch, D.S., 2002, Structure of the submerged San Andreas and San Gregorio fault zones in the Gulf of Farallones as inferred from high-resolution seismic-reflection data, in Parsons, T. (ed.), Crustal structure of the coastal and marine San Francisco Bay region, California: U.S. Geological Survey Professional Paper 1658, p. 77-117.
Lomax, A., 2005, A reanalysis of the hypocentral location and related observations for the Great 1906 California earthquake: Bulletin of the Seismological Society of America, v. 95, p. 861-877.
Ryan, H.F., Parsons, T., and Sliter, R.W., 2008. Vertical tectonic deformation associated with the San Andreas fault zone offshore of San Francisco, California. Tectonophysics, 429 (1-2), p. 209-224.
U.S. Geological Survey and California Geological Survey, 2010, Quaternary fault and fold database for the United States, accessed April 5, 2012, from USGS website: http://earthquake.usgs.gov/hazards/qfaults/.
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, which can be used geographic information systems.
Additionally, to provide a geologic map for the public and geoscience community to aid in
assessments and mitigation of geologic hazards in the San Gregorio coastal region
and to provide sufficient geologic information for land-use and
land-management decisions both onshore and offshore.
This information is not intended for navigational purposes.
Map political location: San Mateo County, California
Compilation scale: 1:24,000
Base maps used are hillshades generated from IfSAR, LiDAR, and multibeam
mapping both onshore and offshore (see Bathymetry--Offshore of Pacifica map area, California, DS 781, for more information).
2007
2010
ground condition
none planned
-122.588071
-122.493750
37.702237
37.540691
Global Change Master Directory (GCMD)
Oceans > Bathymetry/SeafloorTopography > Bathymetry
Oceans > Bathymetry/SeafloorTopography > Seafloor Topography
General
Seafloor Character
Fisheries
Ecosystem
Multibeam
Geology
Bathymetry
Backscatter
Intensity
Ocean Floor Topography
U.S. Geological Survey
USGS
Pacific Coastal and Marine Science Center
CMGP
ISO 19115 Topic Category
geoscientificInformation
environment
oceans
imageryBaseMapsEarthCover
Geographic Names Information System (GNIS)
Pacific Ocean
State of California
Pacifica
San Mateo County
Rockaway Beach
If physical samples or materials are available, constraints on their on-site access
are described in "WR CMG Sample Distribution Policy" at URL:
http://walrus.wr.usgs.gov/infobank/programs/html/main/sample-dist-policy.html
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.
USGS Pacific Coastal and Marine Science Center
Stephen Hartwell
Geologist
physical address
400 Natural Bridges Drive
Santa Cruz
CA
95060
USA
(831) 460-7814
(831) 427-4748
shartwell@usgs.gov
<https://pubs.usgs.gov/ds/781/OffshorePacifica/images/Folds_OffshorePacifica.jpg>
Folds offshore Pacifica.
JPEG
Microsoft Windows Server 2008 R2 Version 6.1 (Build 7601) Service Pack 1; ESRI ArcGIS 10.0.0.2414
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.
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.
Folds were primarily mapped by interpretation of seismic reflection profile data (see S-15-10-NC and F-2-07-NC).
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.
U.S. Geological Survey (USGS) , Coastal and Marine Geology Program (CMGP)
2013
Seismic-reflection data acquisition data of field activity
S-15-10-NC in offshore Pescadero from 08/02/2010 to
08/04/2010
Menlo Park, CA
U.S. Geological Survey (USGS) , Coastal and Marine Geology (CMG)
http://walrus.wr.usgs.gov/infobank/gos/s-15-10-nc.fmeta.xml
http://walrus.wr.usgs.gov/infobank/s/s1510nc/html/s-15-10-nc.meta.html
ASCII lat/long shot point files
20100802
20100804
ground condition
S-15-10-NC
Digital seismic data used to interpret subsurface geologic structure
U.S. Geological Survey (USGS) , Coastal and Marine Geology Program (CMGP)
2013
Geophysical data of field activity F-2-07-NC in Ano Nuevo to
San Francisco from 03/22/2007 to 04/06/2007
Menlo Park, CA
U.S. Geological Survey (USGS) , Coastal and Marine Geology (CMG)
http://walrus.wr.usgs.gov/infobank/gos/f-2-07-nc.fmeta.xml
http://walrus.wr.usgs.gov/infobank/f/f207nc/html/f-2-07-nc.meta.html
ASCII lat/long shot point files
20070322
20070406
ground condition
F-2-07-NC
Digital seismic data used to interpret subsurface geologic structure
Folds were mapped onto shot lines based on the latitude and longitude of seismic picks from field activity
S-15-10-NC.
2010
Folds were mapped onto shot lines based on the latitude and longitude of seismic picks from field activity
F-2-07-NC.
2011
Vector
String
52
WGS 1984 UTM Zone 10N
0.9996
-123.0
0.0
500000.0
0.0
coordinate pair
0.0001
0.0001
Meter
D WGS 1984
WGS 1984
6378137.0
298.257223563
Folds
lines representing mapped folds
This report
FID
Internal feature number.
ESRI
Sequential unique whole numbers that are automatically generated.
Shape
Feature geometry.
ESRI
Coordinates defining the features.
FGDCRefNo
FGDC Digital Cartographic Standard for geologic map symbolization
This report
text field containing the reference number for the FGDC Digital Cartographic Standard for geologic map symbolization
Shape_Length
Length of feature in internal units.
ESRI
Positive real numbers that are automatically generated.
2013
U.S. Geological Survey, Coastal and Marine Geology Program
Stephen R. Hartwell
mailing and physical address
400 Natural Bridges Drive
Santa Cruz
CA
95060-5792
US
831-460-7814
831-427-4748
shartwell@usgs.gov
FGDC Content Standard for Digital Geospatial Metadata
FGDC-STD-001-1998