GRAVITY INTERPRETATION USING FOURIER-TRANSFORMS AND SIMPLE GEOMETRICAL MODELS WITH EXPONENTIAL DENSITY CONTRAST

The decrease of density contrast in sedimentary basins can often be ap proximated by an exponential function. Theoretical Fourier transforms are derived for symmetric trapezoidal, vertical fault, vertical prism, syncline, and anticline models. This is desirable because there are n o equivalent closed form solutions in the space domain for these model s combined with an exponential density contrast. These transforms exhi bit characteristic minima, maxima, and zero values, and hence graphica l methods have been developed for interpretation of model parameters. After applying end corrections to improve the discrete transforms of o bserved gravity data, the transforms are interpreted for model paramet ers. This method is first tested on two synthetic models, then applied to gravity anomalies over the San Jacinto graben and Los Angeles basi n.