This study is an analysis of the U. S. Geological Survey gravity data from Borrego Valley, California. Borrego Valley consists of pre-Tertiary basement underlying the Quaternary age alluvium. The gravity data was obtained by drawing cross-sections perpendicular to the contours on the U.S. Geological Survey residual gravity contour map (Plate 1). These observed data were used in Magix.plus to calculate the depth to bedrock by matching the measured data to the theoretically calculated anomalies. This computed anomaly will give the basement shape and depth. Although the interpretation is non-unique, the ambiguity is decreased by using external constraints on the profile. Each profile contains a point where bedrock depth is zero, a well with a known bedrock depth, and a point where all profiles cross. These constraints help define the shape of the anomaly.
