Preparation of residual gravity maps for the southern Cascade Mountains, Washington using Fourier analysis

Abstract

A continuation of gravity work in the Cascade Mountains of Washington is presented. Baseline gravity data were collected for use in geothermal resource evaluation. The purpose of this report is to describe a Fourier analysis method for separating residual and regional gravity anomalies from a complete Bouguer gravity anomaly field. The technique has been applied to gravity data from the Southern Cascade Mountains, Washington. Residual gravity anomaly maps at a scale of 1:250,000 are presented for various regional wavelength filters, and a power spectrum of the frequency components in the South Cascade gravity data is displayed. No attempt is made to interpret the results of this study in terms of geologic structures.