Olympic Coast National Marine Sanctuary Science section includes Seafloor Mapping, Oceanography, Deep Sea Coral and Sponges, Wildlife Research, Coastal Habitats, Citizen Science, Ecosystem Processes, Research Surveys, and Research Assets
Olympic Coast National Marine Sanctuary Science section includes Seafloor Mapping, Oceanography, Deep Sea Coral and Sponges, Wildlife Research, Coastal Habitats, Citizen Science, Ecosystem Processes, Research Surveys, and Research Assets
Olympic Coast National Marine Sanctuary Science section includes Seafloor Mapping, Oceanography, Deep Sea Coral and Sponges, Wildlife Research, Coastal Habitats, Citizen Science, Ecosystem Processes, Research Surveys, and Research Assets Olympic Coast National Marine Sanctuary Science section includes Seafloor Mapping, Oceanography, Deep Sea Coral and Sponges, Wildlife Research, Coastal Habitats, Citizen Science, Ecosystem Processes, Research Surveys, and Research Assets

Multibeam Seafloor Mapping
for Substrate 2011

R/V Pacific Storm Multibeam Seafloor Mapping Survey
P.I. Dr. Chris Goldfinger, Oregon State University; Chief Scientist Nancy Wright OCNMS
Coral Reef Conservation Program

Download final report here (820k pdf)

Download backscatter file here (361Mb raster zip)

Download multibeam file here (155Mb raster zip)

From July 13 to July 23 the Oregon State University Seafloor Mapping Lab and Olympic Coast National Marine Sanctuary conducted a multibeam (MBES) sonar survey of ~200 km2 in the north-western quadrant of OCNMS. The purpose of this survey was to collect data from which to extract information on the presence of hard substrate conducive to coral and sponge community formation. Three contiguous areas were mapped. This preliminary note on sedimentary and geomorphic detail delineates only the northernmost area.

For this survey, navigation was collected with a Navcom Starfire 3050 subscription satellite based carrier wave differential GPS, with ~ 15 cm horizontal accuracy. Motion control was via an Applanix Pos MV inertial/GPS attitude system. The data were collected with a Reson 8101ER MBES, acquired with Hypack/Hysweep software, and processed at 8 m resolution using CARIS software; the backscatter was processed in Fledermaus FMGeocoder software and final products were created in ArcMap. Samples were collected at 19 strategic sites to groundtruth the acoustic data using a shipek grab sampler.

Map of multibeam imagery which shows a large outcrop amidst sand at the edge of the shelf

Multibeam imagery shows evidence of hard or compacted substrate (lighter color) in the northern section of the mapped area.


In the multibeam backscatter, only the northern area showed evidence of hard or compacted substrate mixed with gravel beds, semi-lithified sediments, and coarse and fine sand. The northern area exhibits a large central outcrop with bathymetric relief of ~35 m. Overall, the broad low relief area, northwest of Juan de Fuca Canyon is an uplifted anticlinal structure trending NE-SW, with strike ridges of exposed hard substrate that wrap around the nose of a NE plunging anticline, creating a pattern of hard ridges with 3-5 m relief in a boomerang shape pointing toward the ENE. The active anticline appears to control the SW trend of Juan de Fuca Canyon which is 150-170 m deep adjacent to the uplifted bank. The uplifted hard ridges were sampled several times and are consolidated siltstones and mudstones. On the backscatter mosaic, these are the relatively dark areas corresponding to narrow ridges in the bathymetry. Overlaid on this bedrock are thin deposits of glacial outwash rounded gravels, coarse sands and shell hash that fill the narrow gullies between the bedrock ridges. This material is the bright areas on the backscatter imagery, and also in formed into several terminal moraines or glacial push ridges that are draped over the bedrock framework. Other darker (and deeper) areas surrounding the uplifted bank are likely coarse sand, though these areas were not sampled. The gravels and sands are brighter reflectors as they form a good specular reflection with the 240 kHz Reson sonar, and because these gravels are likely transported harder rock material than the soft exposed siltstone bedrock material.

Several physical samples taken by the Shipek grab sampler included sponge and possible coral fragments. Several samples on the rock substrate returned remnant coral material (sites 5, 13, 11) indicating that the bedrock ridges may support living corals, though densities are unknown. Abundant substrate of this type is available on the low relief uplift.

The backscatter data from this survey is available as a GIS geotif file called "pacific_storm_2011_backscatter.zip" and the bathymetry for this geographic area has been incorporated in the consolidated multibeam map for OCNMS as of 2011 called "ocnms_multibeam_2011.zip". The data can be downloaded at the top of this page. All data is produced in ESRI ArcGIS 10, NAD83 UTM 10.

For information contact Nancy Wright.



Contact for page content: Nancy Wright
photo of a buoy on the ocean
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