These metadata describe acoustic-backscatter data collected during a 2016 SWATHPlus-M survey offshore the Elwha River mouth, Strait of Juan de Fuca, Washington. Data were collected and processed by the U.S. Geological Survey (USGS), Pacific Coastal and Marine Science Center (PCMSC) with fieldwork activity number 2016-605-FA. The acoustic-backscatter data are provided as a GeoTIFF image in UTM, zone 10, NAD83 coordinates.

Acoustic backscatter data were collected by the U.S. Geological Survey in July 2008 in the northern Santa Barbara Channel in southern California. Data were collected aboard the R/V Parke Snavely, during USGS Field Activity S-9-08-SC, using a bathymetric sidescan system.

These metadata describe acoustic backscatter data collected during a 2008 SWATHPlus-M survey offshore Tijuana River Estuary, California. Data were collected and processed by the U.S. Geological Survey (USGS), Pacific Coastal and Marine Science Center (PCMSC) with fieldwork activity number S-5-08-SC. The acoustic backscatter data are provided as a GeoTIFF image.

Spatial surveys of water column acoustic backscatter were performed between May 28 and June 2, 2013, in the mouth of the Columbia River, Oregon and Washington. These data were collected using a Biosonics DTX single-beam echosounder with 430 kHz transducer.

Spatial surveys of water column acoustic backscatter were performed between May 28 and June 2, 2013, in the mouth of the Columbia River, Oregon and Washington. These data were collected using a Biosonics DTX single-beam echosounder with 430 kHz transducer.

2-m resolution acoustic-backscatter data were collected during a July 2019 SWATHPlus survey of Ozette Lake, Washington. Data were collected and processed by the U.S. Geological Survey (USGS), Pacific Coastal and Marine Science Center (PCMSC) with fieldwork activity number 2019-622-FA. The 2-m acoustic-backscatter data are provided as a GeoTIFF image.

This portion of the data release presents acoustic backscatter data from the San Miguel Passage, in the Channel Islands, California. The data were collected in August 2007 by the U.S. Geological Survey, Pacific Coastal and Marine Science Center (USGS, PCMSC) using a 234.5 kHz SEA (AP) Ltd. SWATHplus-M phase-differencing sidescan sonar mounted on the NOAA, Channel Islands National Marine Sanctuary R/V Shearwater as part of the research cruise S-2-07-SC. Data were collected in water depths up to 89 meters. The San Miguel Passage is within the Channel Islands National Marine Sanctuary and is the body of water between the two western-most islands of the chain - Santa Rosa and San Miguel Islands. The data were processed at the USGS, PCMSC to create a 2-meter resolution TIFF raster, presented here.

This portion of the data release presents acoustic backscatter data from the San Miguel Passage, in the Channel Islands, California. The data were collected in August 2007 by the U.S. Geological Survey, Pacific Coastal and Marine Science Center (USGS, PCMSC) using a 234.5 kHz SEA (AP) Ltd. SWATHplus-M phase-differencing sidescan sonar mounted on the NOAA, Channel Islands National Marine Sanctuary R/V Shearwater as part of the research cruise S-2-07-SC. Data were collected in water depths up to 89 meters. The San Miguel Passage is within the Channel Islands National Marine Sanctuary and is the body of water between the two western-most islands of the chain - Santa Rosa and San Miguel Islands. The data were processed at the USGS, PCMSC to create a 2-meter resolution TIFF raster, presented here.

This part of USGS Data Series 781 (Golden, 2019) presents 2-m-resolution acoustic backscatter data for the Offshore of the Eel River, California, map area. Backscatter data were collected by Fugro Pelagos in 2008 using a combination of 400-kHz Reson 7125, 240-kHz Reson 8101, and 100-kHz Reson 8111 multibeam echosounder systems. The data were post-processed by the California State University Monterey Bay Seafloor Mapping Lab. The acoustic backscatter data are available as a georeferenced TIFF image. Within the final 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 composition. 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).

This part of USGS Data Series 781 (Golden, 2019) presents 2-m-resolution acoustic backscatter data for the Offshore of the Eel River, California, map area. Backscatter data were collected by Fugro Pelagos in 2008 using a combination of 400-kHz Reson 7125, 240-kHz Reson 8101, and 100-kHz Reson 8111 multibeam echosounder systems. The data were post-processed by the California State University Monterey Bay Seafloor Mapping Lab. The acoustic backscatter data are available as a georeferenced TIFF image. Within the final 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 composition. 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).