Interactive gravity inversion

Abstract

We have developed a new approach to estimate the location and the geometry of several density anomalies that give rise to a complex and interfering gravity field. The proposed inversion method is implemented in a user‐friendly environment and is similar to interactive modeling but differs from it in automatically fitting the observations and in requiring from the interpreter only the interactive definition of the sources outlines expressed by simple geometric elements such as points and line segments. The method then estimates sources closest to the specified outline to achieve a match between the predicted and observed gravity fields. Each gravity source is assumed to be a homogeneous body with known density contrast; different density contrasts may be assigned to each source. The method's potential utility in producing stable and geologically meaningful results is illustrated by inverting synthetic data produced by complex simulated geological settings comprising closely adjacent gravity sources. The method was also applied to the interfering gravity anomaly produced by metabasalts and metagabbros from a greenstone belt located in Rio Maria region, in Pará state, Brazil, producing solutions consistent with the known geological attributes of the gravity sources.