INVERSION OF THE POWER SPECTRUM FROM GRAVITY-ANOMALIES OF PRISMATIC BODIES

I develop methods for modeling and inversion of gravity anomalies prod uced by prismatic bodies. The forward problem is solved in the wavenum ber domain, where the power spectrum of the gravity anomaly is given b y the product of independent functions that describe depth, thickness, horizontal dimensions, and density of the source body. The solution o f the inverse problem is based on an iterative ridge-regression algori thm, starting from an initial trial of the geometry and density of the source body. This procedure is assessed in a number of examples with both numeric and field data spectra. The method is first tested on the spectrum obtained from simple gravity anomalies and is found to be ca pable of recovering the source parameters. Next the method is applied to gravity data from a survey made near Noranda, Quebec, Canada. This interpretation compares favorably with drillhole data and provides an estimation of the mass of the source body which is similar to previous estimates.