A gravity gradient method for characterizing the post-seismic deformation field for a finite fault

Abstract

SUMMARY Gravity gradients are an effective method for delineating the extent of subsurface density anomalies. The change in subsurface density contrasts due to the seismic deformation gives rise to detectable gravity changes via the dilatational gravity signal or Bouguer anomaly. Solutions for the corresponding gravity gradients of these signals are developed for a vertical strikeslip fault. Gravity gradient solutions exhibit similar spatial distributions as those calculated for Coulomb stress changes, reflecting their physical relationship to the stress changes. The signals’ magnitudes, of the order of 10 −4 E, are beyond the resolution of typical exploration instruments. Improvements to Superconducting Gravity Gradiometers are necessary for gravity gradients to be used as a viable method for the observation of the stress field changes over large spatial scales.