Description: This part of SIM 3319 presents bathymetric contours for several seafloor maps of Offshore Refugio State Beach, California (vector data file is included in "Contours_OffshoreRefugioStateBeach.zip," which is accessible from http://pubs.usgs.ov/ds/781/OffshoreRefugioStateBeach/data_catalog_OffshoreRefugioStateBeach.html). Contours of Offshore Refugio State Beach, California, were clipped from a larger overall contour dataset of all California State Waters within the Santa Barbara Channel. These contours were generated from bathymetry data collected by the U.S. Geological Survey (USGS), by California State University, Monterey Bay, Seafloor Mapping Lab (CSUMB), and by Fugro Pelagos. The USGS conducted mapping within State waters in the summers of 2005, 2006, 2007, and 2008 using a combination of 117 kHz and 234.5 kHz SEA (AP) Ltd. SWATHplus-M phase-differencing sidescan sonars. CSUMB conducted mapping in the summers of 2006 and 2007 using a 244 kHz Reson 8101 multibeam echosounder. Fugro Pelagos conducted multibeam mapping in 2008 using a combination of 400 kHz Reson 7125, 240 kHz Reson 8101, and 100 kHz Reson 8111 multibeam echosounders. Fugro Pelagos also conducted coastal bathymetric and topographic lidar mapping in 2009 for the U.S. Army Corps of Engineers (USACE) Joint Lidar Bathymetry Technical Center of Expertise using the SHOALS-1000T bathymetric and the Leica ALS60 topographic lidar systems. All of these mapping missions combined to collect bathymetry from the 0-m isobath to beyond the 3-nautical mile limit of Californias state waters.
Description: This part of SIM 3319 presents folds for the geologic and geomorphic map (see sheets 10, SIM 3319) of Offshore Refugio Beach, California. The vector data file is included in "Folds_OffshoreRefugioBeach.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshoreRefugioBeach/data_catalog_OffshoreRefugioBeach.html. This map area lies within the Western Transverse Ranges province, north of the southern California Borderland (Fisher and others, 2009). This province has undergone significant north-south compression since the Miocene, and recent global positioning system (GPS) data suggest north-south shortening of about 6 mm/yr (Larson and Webb, 1992). The active west-trending Pitas Point Fault (broad zone including back faults), Red Mountain Fault, and Rincon Creek Fault are some of the structures on which this shortening occurs (e.g., Jackson and Yeats, 1982; Sorlien and others, 2000; Fisher and others, 2009). This fault system, in aggregate, extends for about 100 km through the Ventura and Santa Barbara basins and represents an important earthquake hazard (e.g., Fisher and others, 2009).
Description: This part of SIM 3319 presents folds for the geologic and geomorphic map (see sheets 10, SIM 3319) of Offshore Refugio Beach, California. The vector data file is included in "Folds_OffshoreRefugioBeach.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshoreRefugioBeach/data_catalog_OffshoreRefugioBeach.html. This map area lies within the Western Transverse Ranges province, north of the southern California Borderland (Fisher and others, 2009). This province has undergone significant north-south compression since the Miocene, and recent global positioning system (GPS) data suggest north-south shortening of about 6 mm/yr (Larson and Webb, 1992). The active west-trending Pitas Point Fault (broad zone including back faults), Red Mountain Fault, and Rincon Creek Fault are some of the structures on which this shortening occurs (e.g., Jackson and Yeats, 1982; Sorlien and others, 2000; Fisher and others, 2009). This fault system, in aggregate, extends for about 100 km through the Ventura and Santa Barbara basins and represents an important earthquake hazard (e.g., Fisher and others, 2009).
Description: This part of SIM 3319 presents the geologic and geomorphic map (see sheets 10, SIM 3319) of Offshore Refugio Beach, California. The vector data file is included in "Geology_OffshoreRefugioBeach.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshoreRefugioBeach/data_catalog_OffshoreRefugioBeach.html. The offshore Refugio Beach map area largely consists of a gently offshore-dipping (<1 degree) shelf (10 to ~ 90 m) underlain by sediments derived primarily from relatively small coastal watersheds draining the Santa Ynez Mountains. Nearshore and shelf deposits are primarily sand (Qms) at depths less than about 45 m and more fine-grained sediment - very fine sand, silt and clay (Qmsf), at depths greater than about 45 m. The boundary between Qms and Qmsf is based on observations and extrapolation from sediment sampling (for example, Reid and others, 2006) and camera groundtruthing. The Qms-Qmsf boundary is transitional and approximate, expected to shift based on seasonal to annual to decadal scale cycles in wave climate, sediment supply, and sediment transport. Fine-grained deposits similar to Qmsf also occur below the shelfbreak on the upper slope at water depths greater than 90 m, where they are broken out as a separate unit (Qmsl) based on their location and geomorphology. More coarse-grained deposits recognized on the basis of high backscatter and in some cases moderate seafloor relief have two modes of occurrence. In the relative nearshore (10 to 30 m water depth), coarse-grained strata (Qmsc) underlie laterally coalescing and discontinuous bars at the mouths of steep coastal watersheds. Coarser-grained sediments also form several distinct lobes (Qmscl) in water depths of 25 to 70 m, about 600 to 3,000 m offshore. The lobes range in size from ~100,000 m2 to ~1.5 km2 and are mapped on the basis of high backscatter and subtle positive seafloor relief. These coarse-grained strata were clearly derived from fluvial point sources in the adjacent, steep Santa Ynez Mountains. Bedrock exposures in the nearshore west of El Capitan are assigned to the Miocene Monterey Formation based on proximity to coastal outcrops mapped by Dibblee (1981a, b). Much of the outer shelf (water depths > 70 m) is also underlain by undifferentiated Tertiary bedrock (Tbu). Based on the regional cross sections constrained by deep seismic-reflection data and borehole logs (Heck, 1998; Tennyson and Kropp, 1998; Forman and Redin, 2005; Redin, 2005) and high-resolution seismic-reflection data coupled with proprietary oil industry dartcore data (Ashley, 1977), these outer-shelf outcrops consist of the Miocene Sisquoc Formation and the Pliocene Repetto and Pico Formations. These rocks have been uplifted in a large, warped, regional south-dipping homocline that formed above the blind, north-dipping North Channel fault. The fault tip is inferred at about 1.5 sec TWT (~2 km) about 6 to 7 km offshore, beneath the slope and just outside California's State Waters. Bedrock that underlies some parts of the shelf is overlain by a thin (< 1 m?) sediment veneer, recognized based on high backscatter, flat relief, continuity with moderate to high relief bedrock outcrops, and (in some cases) high-resolution, seismic-reflection data (Qms/Qtbu. Qms/Tbu, Qms/Tm). These sediment layers are likely ephemeral - they may or may not be present based on storms, seasonal/annual patterns of sediment movement, or longer-term climate cycles. This area has a long history of petroleum production (Barnum, 1998), and grouped to solitary pockmarks (Qmp) caused by gas seeps are common features in the offshore Refugio map area. Shell discovered the Molino gas field in 1962, 4 km offshore in the southwest part of the map area. Production, by onshore directional drilling of an anticlinal trap, has been underway since the 1960's (Galloway, 1998).
Description: This part of SIM 3319 presents the habitat map of the seafloor (see sheet 7) offshore of Refugio State Beach, California (vector data file is included in "Habitat_RefugioStateBeach.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshoreRefugioStateBeach/data_catalog_OffshoreRefugioStateBeach.html). Using multibeam echosounder (MBES) bathymetry and backscatter data, potential marine benthic habitat maps were constructed. The habitats were based on substrate types and documented or "ground truthed" using underwater video images and seafloor samples obtained by the USGS. These maps display various habitat types ranging from flat, soft consolidated sediment-covered seafloor to hard, deformed (folded) or highly rugose and differentially eroded bedrock exposures. Rugged, high relief rocky outcrops that have been eroded to form ledges and small caves are ideal habitat for rockfish (Sebastes spp.) and other bottom fish such as lingcod (Ophiodon elongatus). Habitat maps will be presented in a map format generated in a GIS (ArcMap) and both digital and hard copy versions will be produced.
Description: This part of SIM 3319 presents the seafloor-character map (see sheet 7) offshore of Refugio State Beach, California (raster data file is included in "SeafloorCharacter_OffshoreRefugioStateBeach.zip," which is accessible from http://pubs.usgs.ov/ds/781/OffshoreRefugioStateBeach/data_catalog_OffshoreRefugioStateBeach.html). This raster-format seafloor-character map shows five substrate classes of Offshore of Refugio State Beach, California. The substrate classes mapped in this area have been divided into the following California Marine Life Protection Act depth zones: Depth Zone 2 (intertidal to 30 m); Depth Zone 3 (30 to 100 m); and Depth Zone 4 (100 to 200 m). In addition, the following slope classes are represented on this map (Coastal and Marine Ecological Classification Standard slope zones are shown in parentheses): Slope Class 1, 0° to 5° (flat) and Slope Class 2, 5° to 30° (sloping). Depth Zone 1 (intertidal); Depth Zone 5 (greater than 200 m); Slope Class 3, 30° to 60° (steeply sloping); and Slope Class 4, 60° to 90° (vertical) are not present in this map area. The map is created using a supervised classification method described by Cochrane (2008), available at http://doc.nprb.org/web/research/research%20pubs/615_habitat_mapping_workshop/Individual%20Chapters%20High-Res/Ch13%20Cochrane.pdf. References Cited: California Department of Fish and Game, 2008, California Marine Life Protection Act master plan for marine protected areas; Revised draft: California Department of Fish and Game, accessed April 5 2011, at http://www.dfg.ca.gov/mlpa/masterplan.asp. Cochrane, G.R., 2008, Video-supervised classification of sonar data for mapping seafloor habitat, in Reynolds, J.R., and Greene, H.G., eds., Marine habitat mapping technology for Alaska: Fairbanks, University of Alaska, Alaska Sea Grant College Program, p. 185-194, accessed April 5, 2011, at http://doc.nprb.org/web/research/research%20pubs/615_habitat_mapping_workshop/Individual%20Chapters%20High-Res/Ch13%20Cochrane.pdf. Sappington, J.M., Longshore, K.M., and Thompson, D.B., 2007, Quantifying landscape ruggedness for animal habitat analysis--A case study using bighorn sheep in the Mojave Desert: Journal of Wildlife Management, v. 71, p. 1419-1426.
Description: This part of SIM 3319 presents data for the bathymetry and shaded-relief maps (see sheets 1, 2, SIM 3319) of the Offshore of Refugio State Beach map area, California. The raster data file for the shaded-relief map is included in "BathymetryHS_OffshoreRefugioStateBeach.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshoreRefugioStateBeach/data_catalog_OffshoreRefugioStateBeach.html. The bathymetry and shaded-relief maps of Offshore of Refugio Beach Area, California, were generated from bathymetry data collected by the U.S. Geological Survey (USGS), and by Fugro Pelagos, for the U.S. Army Corps of Engineers (USACE) Joint Lidar Bathymetry Technical Center of Expertise. The offshore region was mapped by the USGS in 2008, using a 234.5-kHz SEA (AP) Ltd. SWATHplus-M phase-differencing sidescan sonar. The nearshore bathymetry and coastal topography were mapped for USACE by Fugro Pelagos in 2009, using the SHOALS-1000T bathymetric-lidar and Leica ALS60 topographic-lidar systems. All these mapping missions combined to collect bathymetry from the 0-m isobath to beyond the 3-nautical-mile limit of California¡s State Waters.
Description: This part of SIM 3319 presents data for part of the acoustic-backscatter map (see sheet 3, SIM 3319) of Offshore Refugio State Beach map area, California. The raster data file is included in "Backscatter_OffshoreRefugioStateBeach.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshoreCefugioStateBeach/data_catalog_OffshoreefugioStateBeach.html. The acoustic-backscatter map of Offshore Refugio Beach Area was generated from backscatter data collected by the U.S. Geological Survey (USGS). The USGS mapped this region in the summer 2008 using a 234.5 kHz SEA (AP) Ltd. SWATHplus-M phase-differencing sidescan sonar. These data were later re-processed in 2012. Within the acoustic-backscatter imagery, brighter tones indicate higher backscatter intensity, and darker tones indicate lower backscatter intensity. The intensity represents a complex interaction between the acoustic pulse and the seafloor, as well as characteristics within the shallow subsurface, providing a general indication of seafloor texture and sediment type. Backscatter intensity depends on the acoustic source level; the frequency used to image the seafloor; the grazing angle; the composition and character of the seafloor, including grain size, water content, bulk density, and seafloor roughness; and some biological cover. Harder and rougher bottom types such as rocky outcrops or coarse sediment typically return stronger intensities (high backscatter, lighter tones), whereas softer bottom types such as fine sediment return weaker intensities (low backscatter, darker tones).
Description: This part of SIM 3319 presents data for the bathymetry and shaded-relief maps (see sheets 1, 2, SIM 3319) of the Offshore of Refugio State Beach map area, California. The raster data file for the bathymetry map is included in "Bathymetry_OffshoreRefugioStateBeach.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshoreRefugioStateBeach/data_catalog_OffshoreRefugioStateBeach.html. The bathymetry and shaded-relief maps of Offshore of Refugio Beach Area, California, were generated from bathymetry data collected by the U.S. Geological Survey (USGS), and by Fugro Pelagos, for the U.S. Army Corps of Engineers (USACE) Joint Lidar Bathymetry Technical Center of Expertise. The offshore region was mapped by the USGS in 2008, using a 234.5-kHz SEA (AP) Ltd. SWATHplus-M phase-differencing sidescan sonar. The nearshore bathymetry and coastal topography were mapped for USACE by Fugro Pelagos in 2009, using the SHOALS-1000T bathymetric-lidar and Leica ALS60 topographic-lidar systems. All these mapping missions combined to collect bathymetry from the 0-m isobath to beyond the 3-nautical-mile limit of California¡s State Waters.