Metadata: Identification_Information: Citation: Citation_Information: Originator: H.G. Greene Originator: M.W. Manson Originator: B.E. Dieter Originator: S.L. Ross Originator: S.R. Hartwell Originator: S.Y. Johnson Originator: J.T. Watt Publication_Date: 2014 Title: Geology and geomorphology--Offshore of Half Moon Bay Map Area, California Geospatial_Data_Presentation_Form: polygon shapefile digital data Larger_Work_Citation: Citation_Information: Originator: Guy R. Cochrane Originator: Peter Dartnell Originator: H. Gary Greene Originator: Samuel Y. Johnson Originator: Nadine E. Golden Originator: Stephen R. Hartwell Originator: Brian E. Dieter Originator: Michael W. Mansion Originator: Ray W. Sliter Originator: Stephanie L. Ross Originator: Janet T. Watt Originator: Charles A. Endris Originator: Rikk G. Kvitek Originator: Brian D. Edwards Originator: Eleyne L. Phillips Originator: Mercedes D. Erdey Originator: Carrie K. Bretz Originator: John L. Chin Originator: Carrie K. Bretz Publication_Date: 2014 Title: California State Waters Map Series--Offshore of Half Moon Bay map area, California Geospatial_Data_Presentation_Form: map Series_Information: Series_Name: Open-File Report Issue_Identification: OFR 2014-1214 Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Online_Linkage: http://pubs.usgs.gov/of/2014/1214/ Larger_Work_Citation: Citation_Information: Originator: Nadine E. Golden Publication_Date: 2013 Title: California State Waters Map Series Data Catalog Geospatial_Data_Presentation_Form: database Series_Information: Series_Name: Data Series Issue_Identification: DS 781 Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Online_Linkage: http://pubs.usgs.gov/ds/781/ Description: Abstract: This part of DS 781 presents data for the geologic and geomorphic map of the Offshore of Half Moon Bay map area, California. The vector data file is included in "Geology_OffshoreHalfMoonBay.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshoreHalfMoonBay/data_catalog_OffshoreHalfMoonBay.html. The continental shelf within California's State waters in the Half Moon Bay area is shallow (0 to ~55 m) and flat with a very gentle (less than 0.5 degrees) offshore dip. The morphology and geology of this shelf result from the interplay between local tectonics, sea-level rise, sedimentary processes, and oceanography. Tectonic influences are related to local faulting and uplift (see below). Sea level has risen about 125 to 130 m over the last ~21,000 years (for example, Lambeck and Chappel, 2001; Gornitz, 2009), leading to progressive eastward migration (a few tens of km) of the shoreline and wave-cut platform and associated transgressive erosion and deposition (for example, Catuneanu, 2006). The Offshore of Half Moon Bay map area is now an open-ocean shelf that is subjected to full, and sometimes severe, wave energy and strong currents. Given the relatively shallow depths and high energy, modern shelf deposits are mostly sand (unit Qms). More coarse-grained sands and gravels (units Qmss and Qmsc) are primarily recognized on the basis of bathymetry and high backscatter (Bathymetry; Backscatter A [8101]; and Backscatter B [7125]--Offshore Half Moon Bay, California, DS 781). Unit Qmsc occurs only as a nearshore bar (~ 10 m water depth) just south of the Pillar Point Harbor jetty. Unit Qmss forms erosional lags in rippled scour depressions (see, for example, Cacchione and others, 1984) and is more extensive and distributed, with the largest concentrations occurring at water depths of 30 to 55 m offshore Pillar Point, and in the nearshore (depths of 5 to 15 m) south of Pillar Point Harbor and north-northwest of Pillar Point. Such rippled-scour depressions are common along this stretch of the California coast where offshore sandy sediment can be relatively thin (thus unable to fill the depressions) due to both lack of sediment supply from rivers and to significant sediment erosion and offshore transport during large winter storms. Although the general areas in which both unit Qmss scour depressions and unit Qmsc bars occur are not likely to change substantially, the boundaries of the unit(s) are likely ephemeral, changing seasonally and during significant storm events. Areas where shelf sediments form thin (< 2.5 m or less) veneers over low relief Purisima Formation (upper Miocene and Pliocene) or undifferentiated Cretaceous and (or) Tertiary bedrock are mapped as units Qms/Tp and Qms/TKu. These areas are recognized based on the combination of flat relief, continuity with moderate to high relief bedrock outcrops, high-resolution seismic-reflection data (see field activity S-15-10-NC), and in some cases moderate to high backscatter. These units are regarded as ephemeral and dynamic sediment layers that may or may not be present at a specific location based on storms, seasonal/annual patterns of sediment movement, or longer-term climate cycles. In a nearby similarly high-energy setting, Storlazzi and others (2011) have described seasonal burial and exhumation of submerged bedrock in northern Monterey Bay. Offshore bedrock outcrops are mapped as the upper Miocene and Pliocene Purisima Formation (unit Tp), the Cretaceous granitic rocks of Montara Mountain (unit Kgr), and undivided sedimentary rocks of Cretaceous and (or) Tertiary age (unit TKu). These units are delineated through extending outcrops and trends from mapped onshore geology and from their distinctive surface textures as revealed by high-resolution bathymetry (Bathymetry--Offshore Half Moon Bay, California, DS 781). Purisima Formation outcrops form distinctive straight to curved "ribs," caused by differential erosion of more- and less-resistant lithologies (for example, sandstone and mudstone). In contrast, granitic rocks have a densely cross-fractured surface texture. Map unit polygons were digitized over underlying 2-meter base layers developed from multibeam bathymetry and backscatter data. The bathymetry and backscatter data were collected between 2006 and 2010. References Cited Cacchione, D.A., Drake, D.E., Grant, W.D., and Tate, G.B., 1984. Rippled scour depressions of the inner continental shelf off central California: Journal of Sedimentary Petrology, v 54, p. 1280-1291. Catuneanu, O., 2006, Principles of Sequence Stratigraphy: Amsterdam, Elsevier, 375 p. Gornitz, V., 2009, Sea level change, post-glacial, in Gornitz, V., ed., Encyclopedia of Paleoclimatology and Ancient Environments: Encyclopedia of Earth Sciences Series. Springer, pp. 887-893. Lambeck, K., and Chappell, J., 2001, Sea level change through the last glacial cycle: Science, v. 292, p. 679-686. Purpose: 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. Supplemental_Information: 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 Hillshade--Offshore Half Moon Bay, California, DS 781,for more information). Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 2006 Ending_Date: 2010 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: none planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -122.58 East_Bounding_Coordinate: -122.42 North_Bounding_Coordinate: 37.55 South_Bounding_Coordinate: 37.38 Keywords: Theme: Theme_Keyword_Thesaurus: Global Change Master Directory (GCMD) Theme_Keyword: Oceans > Bathymetry/SeafloorTopography > Bathymetry Theme_Keyword: Oceans > Bathymetry/SeafloorTopography > Seafloor Topography Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: geoscientificInformation Theme_Keyword: environment Theme_Keyword: oceans Theme_Keyword: imageryBaseMapsEarthCover Place: Place_Keyword_Thesaurus: Geographic Names Information System (GNIS) Place_Keyword: Pacific Ocean Place_Keyword: State of California Place_Keyword: Half Moon Bay Place_Keyword: San Mateo County Place_Keyword: Pillar Point Place_Keyword: Pillar Point Harbor Access_Constraints: 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 Use_Constraints: 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. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: USGS Pacific Coastal and Marine Science Center Contact_Person: Stephen Hartwell Contact_Position: Geologist Contact_Address: Address_Type: physical address Address: 400 Natural Bridges Drive City: Santa Cruz State_or_Province: CA Postal_Code: 95060 Country: USA Contact_Voice_Telephone: (831) 460-7814 Contact_Facsimile_Telephone: (831) 427-4748 Contact_Electronic_Mail_Address: shartwell@usgs.gov Native_Data_Set_Environment: Microsoft Windows Server 2008 R2 Version 6.1 (Build 7601) Service Pack 1; ESRI ArcGIS 10.0.0.2414 Browse_Graphic: Browse_Graphic_File_Name: Browse_Graphic_File_Description: Geology offshore Half Moon Bay. Browse_Graphic_File_Type: JPEG Data_Quality_Information: Logical_Consistency_Report: 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. Completeness_Report: 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. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Polygons were primarily mapped by one of the following methods: (1) interpretation of 2-meter-resolution hillshaded bathymetry data from bathymetric lidar and sonar surveys (see Bathymetry--Offshore Half Moon Bay, California, DS 781); (2) interpretation of 2-meter-resolution amplitude (backscatter) data from bathymetric sonar surveys (see BackscatterA_8101 and BackscatterB_7125--Offshore Half Moon Bay, California, DS 781); (3) interpretation of 2-meter interpretation of seismic-reflection-profile data (see field activity S-15-10-NC). 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 database. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: Carrie K. Bretz Originator: Rikk G. Kvitek Originator: Peter Dartnell Originator: Eleyne L. Phillips Publication_Date: 2013 Title: Bathymetry--Offshore of Half Moon Bay Map Area, California Geospatial_Data_Presentation_Form: raster digital data Series_Information: Series_Name: Data Series Issue_Identification: DS 781 Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Other_Citation_Details: See metadata for bathymetry ("Bathymetry_OffshoreHalfMoonBay_metadata.txt") in DS 781 for source data and postprocessing/reprocessing information. Online_Linkage: http://pubs.usgs.gov/ds/781/OffshoreHalfMoonBay/metadata/Bathymetry_OffshoreHalfMoonBay_metadata.txt Type_of_Source_Media: digital file of gridded bathymetry data (ArcInfo GRID) Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 2006 Ending_Date: 2009 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: DS 781 Source_Contribution: Gridded bathymetry data (2-meter resolution). Source_Information: Source_Citation: Citation_Information: Originator: Carrie K. Bretz Originator: Rikk G. Kvitek Originator: Peter Dartnell Originator: Eleyne L. Phillips Publication_Date: 2013 Title: Backscatter--Offshore of Half Moon Bay Map Area, California Geospatial_Data_Presentation_Form: raster digital data Series_Information: Series_Name: Data Series Issue_Identification: DS 781 Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Other_Citation_Details: See metadata for backscatter data ("BackscatterA_8101_OffshoreHalfMoonBay_metadata.txt" and "BackscatterB_7125_OffshoreHalfMoonBay_metadata.txt") in DS 781 for amplitude source data and postprocessing/reprocessing information. Online_Linkage: http://pubs.usgs.gov/ds/781/OffshoreHalfMoonBay/metadata/BackscatterA_8101_OffshoreHalfMoonBay_metadata.txt Online_Linkage: http://pubs.usgs.gov/ds/781/OffshoreHalfMoonBay/metadata/BackscatterB_7125_OffshoreHalfMoonBay_metadata.txt Type_of_Source_Media: digital file of gridded amplitude data (ArcInfo GRID) Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 2006 Ending_Date: 2007 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: DS 781 Source_Contribution: Gridded amplitude data (2-meter resolution). Source_Information: Source_Citation: Citation_Information: Originator: U.S. Geological Survey (USGS) , Coastal and Marine Geology Program (CMGP) Publication_Date: 2013 Title: Seismic-reflection data acquisition data of field activity S-15-10-NC in offshore Pescadero from 08/02/2010 to 08/04/2010 Publication_Information: Publication_Place: Menlo Park, CA Publisher: U.S. Geological Survey (USGS) , Coastal and Marine Geology (CMG) Online_Linkage: http://walrus.wr.usgs.gov/infobank/gos/s-15-10-nc.fmeta.xml Online_Linkage: http://walrus.wr.usgs.gov/infobank/s/s1510nc/html/s-15-10-nc.meta.htm Type_of_Source_Media: ASCII lat/long shot point files Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20100802 Ending_Date: 20100804 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: S-15-10-NC Source_Contribution: Digital seismic data used to interpret subsurface geologic structure Process_Step: Process_Description: Faults were mapped onto shot lines based on the latitude and longitude of seismic picks from field activity S-15-10-NC. Process_Date: 2012 Process_Step: Process_Description: Map unit polygons were digitized over underlying 2-meter 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. Process_Date: 2012 Process_Step: Process_Description: 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 was generated at the NAVD88 +1.46 m contour, defined as the operational MHW shoreline by Weber and others (2005). 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. The transformed boundary is contained within the WGS84 "contours" feature class and identified as a water boundary in the associated representation rules. Only data for offshore map units are released digitally in this publication. For onshore geology see Brabb (1980), Brabb and others (1998), California Geological Survey (1982, 2002), Weber and Lajoie (1980), and Witter and others (2006). References Cited: Brabb, E.E., 1980, Preliminary Geologic Map of the La Honda and Half Moon Bay Quadrangles, San Mateo County, California: U.S. Geological Survey Open-File Report 1980-0245, scale 1:24,000. Brabb, E.E., Graymer, R.W., and Jones, D.L., 1998, Geology of the Onshore Part of San Mateo County, California: A Digital Database: U.S. Geological Survey Open-File Report 98-137, scale 1:62,500. California Geological Survey, 1982, Alquist-Priolo Earthquake Fault Zone Map of Franklin Point quadrangle, scale 1:24,000. California Geological Survey, 2002, CD 2002-01, Fault Evaluation Reports prepared under the Alquist-Priolo Earthquake Fault Zoning Act, Region 1, Central California. Weber, K.M., List, J.H., and Morgan, K.L., 2005, An operational Mean High Water datum for determination of shoreline position from topographic lidar data: U.S. Geological Survey Open-File Report 2005-1027, available at http://pubs.usgs.gov/of/2005/1027/. Weber, G.E., and Lajoie, K.R., 1980, Map of Quaternary Faulting along the Half Moon Bay Fault Zone, San Mateo and Santa Cruz Counties, California: U.S. Geological Survey Open-File Report 1980-0907, scale 1:24,000. Witter, R.C., Knudsen, K.L., Sowers, J.M., Wentworth, C.M., Koehler, R.D., Randolph, C.E., Brooks, S.K., and Gans, K.D., 2006, Maps of Quaternary Deposits and Liquefaction Susceptibility in the Central San Francisco Bay Region, California, U.S. Geological Survey Open-File Report 06-1037, scale 1:24,000. Process_Date: 2011 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Vector Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: GT-polygon composed of chains Point_and_Vector_Object_Count: 487 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Map_Projection: Map_Projection_Name: WGS 1984 UTM Zone 10N Transverse_Mercator: 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_Coordinate_Information: Planar_Coordinate_Encoding_Method: coordinate pair Coordinate_Representation: Abscissa_Resolution: 0.001 Ordinate_Resolution: 0.001 Planar_Distance_Units: Meter Geodetic_Model: Horizontal_Datum_Name: D WGS 1984 Ellipsoid_Name: WGS 1984 Semi-major_Axis: 6378137.0 Denominator_of_Flattening_Ratio: 298.257223563 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: MapUnitPolys Entity_Type_Definition: Polygons representing geologic / geomorphic map units Entity_Type_Definition_Source: This report Attribute: Attribute_Label: OBJECTID Attribute_Definition: Internal feature number. Attribute_Definition_Source: ESRI Attribute_Domain_Values: Unrepresentable_Domain: Sequential unique whole numbers that are automatically generated. Attribute: Attribute_Label: Shape Attribute_Definition: Feature geometry. Attribute_Definition_Source: ESRI Attribute_Domain_Values: Unrepresentable_Domain: Coordinates defining the features. Attribute: Attribute_Label: MapUnitAbbrev Attribute_Definition: Map Unit abbreviation Attribute_Definition_Source: This report Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: af Enumerated_Domain_Value_Definition: Artificial fill and anthropogenic material Enumerated_Domain_Value_Definition_Source: This report Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: Qms Enumerated_Domain_Value_Definition: Marine nearshore and shelf deposits Enumerated_Domain_Value_Definition_Source: This report Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: Qmss Enumerated_Domain_Value_Definition: Marine shelf scour depressions Enumerated_Domain_Value_Definition_Source: This report Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: Qmsc Enumerated_Domain_Value_Definition: Coarse-grained marine nearshore and shelf deposits Enumerated_Domain_Value_Definition_Source: This report Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: Qms/Tp Enumerated_Domain_Value_Definition: Sediment-covered Purisima Formation Enumerated_Domain_Value_Definition_Source: This report Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: Qms/TKu Enumerated_Domain_Value_Definition: Sediment-covered undifferentiated sedimentary deposits Enumerated_Domain_Value_Definition_Source: This report Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: Tp Enumerated_Domain_Value_Definition: Purisima Formation Enumerated_Domain_Value_Definition_Source: This report Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: TKu Enumerated_Domain_Value_Definition: Undifferentiated sedimentary deposits Enumerated_Domain_Value_Definition_Source: This report Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: Kgr Enumerated_Domain_Value_Definition: Granitic rocks of Montara Mountain Enumerated_Domain_Value_Definition_Source: This report Attribute: Attribute_Label: MapUnit Attribute_Definition: short description of map unit Attribute_Definition_Source: This report Attribute_Domain_Values: Unrepresentable_Domain: text description of map unit Attribute: Attribute_Label: Shape_Length Attribute_Definition: Length of feature in internal units. Attribute_Definition_Source: ESRI Attribute_Domain_Values: Unrepresentable_Domain: Positive real numbers that are automatically generated. Attribute: Attribute_Label: Shape_Area Attribute_Definition: Area of feature in internal units squared. Attribute_Definition_Source: ESRI Attribute_Domain_Values: Unrepresentable_Domain: Positive real numbers that are automatically generated. Attribute: Attribute_Label: RuleID Attribute_Definition: Representation rule identifier Attribute_Definition_Source: This report Attribute_Domain_Values: Unrepresentable_Domain: 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. Metadata_Reference_Information: Metadata_Date: 2013 Metadata_Review_Date: 20140826 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey, Coastal and Marine Geology Program Contact_Person: Stephen R. Hartwell Contact_Address: Address_Type: mailing and physical address Address: 400 Natural Bridges Drive City: Santa Cruz State_or_Province: CA Postal_Code: 95060-5792 Country: US Contact_Voice_Telephone: 831-460-7814 Contact_Facsimile_Telephone: 831-427-4748 Contact_Electronic_Mail_Address: shartwell@usgs.gov Metadata_Standard_Name: FGDC Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998