J.B.C. Silva, F.S. Oliveira, V.C.F. Barbosa, H.F. de Campos Velho (2005): Gravimetric Inversion Using Entropic Regularization, 9th International Congress of the Brazilian Geophysical Society (SBGF), September 11-14, Salvador (BA), Brazil.

Abstract: e present a new gravity inversion method, which produces an apparent density contrast mapping on the horizontal plane, based on the combination of the minimization of the first-order entropy with the maximization of the zeroth-order entropy. The interpretation model consists of a horizontal grid of 3D vertical prisms, and the parameters to be estimated are the prisms density contrasts. The maximization of the zeroth-order entropy is equivalent to the global smoothness constraint whereas the minimization of the first-order entropy favors solutions presenting abrupt borders, so a judicious combination of both constraints may lead to solutions characterized by regions where the estimated density contrasts are virtually constant, separated by abrupt discontinuities. The method has been applied to synthetic data simulating the presence of intrusive bodies in sediments. The comparison of the results with those obtained with the global smoothness constraint applied to the same data, showed that that both methods locate the sources with good precision, but the entropic regularization delineates the contour of the bodies with greater resolution, even in the case of 100 m wide bodies separated by a distance as small as 50 m.