Combining multispectral sonar imagery of Monterey Canyon with a digital terrain model for seabed characterization
Multifrequency side-looking sonar backscatter data were collected with an instrument towed within the vicinity of the ocean floor through the Monterey Canyon and Fan during September, 1990. The main objective was to examine the textural property variations in the seabed that result from the interaction of erosional and depositional processes within the subsea drainage network on the slope and the large sediment apron that comprises the deep-sea fan. The mapped terrain textures were superimposed on a relief model generated from multibeam bathymetric data. The principal differences in the sediment reflectivity correlate to how far a seafloor site is separated from the path of turbidity currents that have traveled through the drainage network of Monterey Canyon. Also distinct are contrasts in bedrock roughness that have been juxtaposed by transform faulting along the San Gregorio offshore fault system. The backscatter reflectivity caused by exposure of the Franciscan Formation, a tectonic melange, is dissimilar from reflectivity of exposed granite belonging to the Salinian Formation.