Acoustic Reflexivity (Backscatter) Image: Upper Lucia Canyon, Monterey Bay, California, 1998

A 560 square kilometer pockmark field containing approximately 1,500 individual depressions lies to the south of the Sur and Lucia Canyons. These features occur on a slope platform at depths ranging from 900 meters to 1,200 meters. The pockmarks have irregular circular rims and cross-sectional profiles resembling an inverted cone with inward dipping slopes of 5° to 6°. Diameters range from 130 meters to 260 meters, and depths from rim to bottom range from 8-12 meters, with the typical pockmark being 200 meters across and 10 meters deep. Pockmark densities range from 1.5/km2 in the north increasing to 6/km2 in the south. The southern extent of the pockmark field is unknown but almost certainly extends beyond the southern edge of the surveyed area.

A levied channel with associated overbank deposits and abandoned channel scars bisects the pockmark field in an east-west direction. The overbank deposits appear to have obliterated previously existing pocks, while newer pocks form linear strings along partly buried older channels. Elsewhere they are distributed so as to maintain some optimum distance from each other, and only rarely do two or more pockmarks coalesce (Maher et al., 1998).