Cowthkg.tif is a 1000-m resolution grid of sediment thickness derived from contours (cowiso.shp, also in this data set) from 1:1,000,000-scale Map Showing Sediment Isopachs in the Deep-sea Basins of the Pacific Continental Margin, Strait of Juan de Fuca to Point Loma, California (Gardner and others, 1992, 1993a, 1993b). The maximum sediment thickness in this region is 2342 m with a mean value of 359 m.

COWBSMG is a 1000-m resolution grid of depth to basement off of Washington, Oregon, and California constructed from depth to basement contour data (cowbsm.shp, also in this data set) from 1:1,000,000-scale maps (Gardner and others, 1992, 1993a, 1993b). The range in depth to basement in this region is -5582 to -985 m with a mean of -3817 m.

COWBSMG is a 1000-m resolution grid of depth to basement off of Washington, Oregon, and California constructed from depth to basement contour data (cowbsm.shp, also in this data set) from 1:1,000,000-scale maps (Gardner and others, 1992, 1993a, 1993b). The range in depth to basement in this region is -5582 to -985 m with a mean of -3817 m.

Contours of sediment thickness for the deep-sea basins of the Pacific continental margin offshore of Washington, Oregon, and California were were interpreted from GLORIA (Paskevich and others, 2011) sidescan imagery and related seismic-reflection data and were published as maps in paper format (Gardner and others, 1992, 1993a, 1993b).

Contours of sediment thickness for the deep-sea basins of the Pacific continental margin offshore of Washington, Oregon, and California were were interpreted from GLORIA (Paskevich and others, 2011) sidescan imagery and related seismic-reflection data and were published as maps in paper format (Gardner and others, 1992, 1993a, 1993b).

As part of the USGS's California State Waters Mapping Project, sediment thickness for the seafloor within the 3-nautical mile limit between Gaviota and Hueneme Canyon was extracted from seismic-reflection data collected in 2007 (USGS activity (Z-3-07-SC) and 2008 (S-7-08-SC). Sediment thickness ranges from 0 to 65 m with a mean of 12 m and a standard deviation of 15 m.

This part of DS 781 presents data for the sediment-thickness map of the Point Sur to Point Arguello, California, region. The raster data file is included in the “SedimentThickness_PointSurToPointArguello.zip,” which is accessible from https://doi.org/10.5066/P97CZ0T7. As part of the USGS's California State Waters Mapping Project, a 50-m grid of sediment thickness for the seafloor within the 3-nautical mile limit between Point Sur and Point Arguello was generated from seismic-reflection data collected between 2008 and 2014, and supplemented with geologic structure (fault and fold) information following the methodology of Wong (2012). Reference Cited: Wong, F. L., Phillips, E.L., Johnson, S.Y., and Sliter, R.W., 2012, Modeling of depth to base of Last Glacial Maximum and seafloor sediment thickness for the California State Waters Map Series, eastern Santa Barbara Channel, California: U.S. Geological Survey Open-File Report 2012-1161, 16 p. (available at https://pubs.usgs.gov/of/2012/1161/).

This part of DS 781 presents data for the sediment-thickness map of the Point Sur to Point Arguello, California, region. The raster data file is included in the “SedimentThickness_PointSurToPointArguello.zip,” which is accessible from https://doi.org/10.5066/P97CZ0T7. As part of the USGS's California State Waters Mapping Project, a 50-m grid of sediment thickness for the seafloor within the 3-nautical mile limit between Point Sur and Point Arguello was generated from seismic-reflection data collected between 2008 and 2014, and supplemented with geologic structure (fault and fold) information following the methodology of Wong (2012). Reference Cited: Wong, F. L., Phillips, E.L., Johnson, S.Y., and Sliter, R.W., 2012, Modeling of depth to base of Last Glacial Maximum and seafloor sediment thickness for the California State Waters Map Series, eastern Santa Barbara Channel, California: U.S. Geological Survey Open-File Report 2012-1161, 16 p. (available at https://pubs.usgs.gov/of/2012/1161/).

Two 21-day field operations were conducted in 1997 and 1998 in the estuaries and on the inner continental shelf off the northern Oregon and southern Washington coast. These cruises aboard the R/V Corliss were run in order to generate reconnaissance maps of the seafloor geology and the shallow subsurface stratigraphy using sidescan sonar and seismic-reflection mapping techniques. The 1998 cruise also collected sediment grab samples, bottom photographs, and video images to verify the sidescan-sonar imagery and to document the seafloor geology. The combination of these data with previously collected sediment sample data (Robert, 1974; Nittrouer, 1978; and Smith et. al., 1980) has been used to define the extent and lithology of shelf sediments associated with the Columbia River littoral cell. This work is one component of a larger project studying the erosion of the Washington and Oregon coast and is being coordinated by the U.S. Geological Survey and the Washington State Department of Ecology. The reason for collecting these data is to provide a regional synthesis of the offshore geology to support a wide variety of management decisions and to provide a basis for further process-oriented investigations.

Two 21-day field operations were conducted in 1997 and 1998 in the estuaries and on the inner continental shelf off the northern Oregon and southern Washington coast. These cruises aboard the R/V Corliss were run in order to generate reconnaissance maps of the seafloor geology and the shallow subsurface stratigraphy using sidescan sonar and seismic-reflection mapping techniques. The 1998 cruise also collected sediment grab samples, bottom photographs, and video images to verify the sidescan-sonar imagery and to document the seafloor geology. The combination of these data with previously collected sediment sample data (Robert, 1974; Nittrouer, 1978; and Smith et. al., 1980) has been used to define the extent and lithology of shelf sediments associated with the Columbia River littoral cell. This work is one component of a larger project studying the erosion of the Washington and Oregon coast and is being coordinated by the U.S. Geological Survey and the Washington State Department of Ecology. The reason for collecting these data is to provide a regional synthesis of the offshore geology to support a wide variety of management decisions and to provide a basis for further process-oriented investigations.