Nine fault zones, including several possible offshore extensions of the Sur-Naciemento fault, were located and traced on the Continental Margin off Point Ano Nuevo, California by seismic reflection profiling. Plate tectonic theory was combined with regional geology to arrive at the most plausible choice for the Sur-Naciemento fault zone and to generate a brief geologic history of the area.

Proposed OCS Sale No. 53 includes a maximum offering of 242 tracts for oil and gas leasing offshore central and northern California. Tracts comprise 532,258 hectares (1,315,205 acres) on the Federal OCS, ranging seaward from 3 to as far as 27 miles, and lying in water depths from 50 to 750 meters (162 to 2,437 feet). Tracts comprise five distinct subareas, extending from waters opposite Humboldt Bay in northern California to offshore waters opposite Point Conception in central California. There are no Federal oil and gas leases in the area at present. Very minor exploratory drilling has occurred in some areas previously. Because it is frontier area, the exact extent of oil and gas resources which might be present is somewhat uncertain. The U.S. Geological Survey estimates the most probable resource amounts at 548 million barrels of oil and 621 billion cubic feet of gas. Four of the subareas are regarded as oil prone, while all five are regarded as also likely containing gas. Pending final decision by the Secretary of the Interior, the proposed lease Sale is tentatively scheduled for May 1981.