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Scotian Slope Non-exclusive Multibeam Survey Conducted by C & C Technologies
November 20, 2000 - C&C Technologies, Inc. of Lafayette, Louisiana USA completed a multibeam bathymetry and imagery survey of the Canadian Scotian Slope in June of 2000. Marathon, Murphy, Norsk Hydro, and PanCanadian sponsored this non-exclusive survey, which encompassed 28,000 square kilometers of the lease blocks ranging in depth from 600 to 3500 meters. These data are contributing directly to several issues relating to hydrocarbon prospectively, surficial geohazards, and environmental conditions at the seabed.
The multibeam bathymetry data, with a pixel size of approximately 30 meters, reveal the complex seabed morphology of the Scotian Slope. The eastern part of the survey area is highly dissected by canyons, with broad flat floors that show no evidence of recent sediment failure. The western part of the survey area is much smoother, but large areas of the seabed appear to have surficial failures. Many of these failures in deeper water have linear headscarps, developed along faults previously imaged with high-resolution seismic profiles. Such faults are targets for investigation of surface seeps using ROV technology.
The multibeam imagery data are being used to derive a regional assessment of the character of seabed erosion and the distribution of failures throughout the Scotian Slope where little data exist on these issues. They are allowing for the interpretation of the character of sediment failure features at the seabed, the identification of ?fresh? failures, the distribution of head scarps and their relationship to sub-surface features known from seismic profiles. Gradients on head scarps allow direct estimation of the strength of seabed sediment. Many of the large failures on the Scotian Slope extend from one lease block to another and therefore their interpretation requires regional information. The spatial resolution of multibeam is higher than 3-D seismic and a more regional coverage is provided.
This multibeam data has also provided precise targeting of seabed features for the sediment-sampling program performed by the Geological Survey of Canada (Atlantic) at the Bedford Institute of Oceanography. As a partner with the industry group, GSCA performed a 30-day confirmation cruise in August 2000 acquiring high-resolution seismic profiles and piston cores. The results are being used to ground-truth the multibeam imagery and to interpret the geohazards including slope stability on the lease block area, the age of past failures, the age of slip features on near surface faults, and the distribution of failure scarps and their relationship to sub-surface features. GSCA is performing the analysis with the collaborating partners in industry and universities including Dalhousie and Saint Mary's.