As part of a study by the U.S. Geological Survey of the geology and geophysics of the Elk Hills oil field (U.S. Naval Petroleum Reserve No. 1), a detailed gravity survey is being conducted over the area of the known hydrocarbon reservoirs and the surrounding region. An extremely accurate survey is being conducted to use the results for isolation of small anomalies that are possibly attributable to accumulations of petroleum and natural gas [McCulloh, 1967].
An initial survey of 615 stations is completed over 250 km2 centered on the west half of the Reserve (Figure 1). A similar survey, with an additional 600 stations planned, is in progress for an area of about 260 km2 over the eastern portion of the reserve. Elevations are known to the closest ±3 cm and horizontal positions to ±15 meters. Measurements of gravity at the surface appear to be reliable to ±0.01 mgal. The entire network of gravity stations is tied to stations 268 of Chapman  in the town of McKittrick.