Rapid gravity gradiometry terrain correction via adaptive quadtree mesh discretization

Abstract

We present a method for modelling the terrain response in gravity gradiometry surveys utilizing an adaptive quadtree mesh discretization. The data-dependent method is tailored to provide rapid and accurate spatial terrain corrections for ground, seaborne, or draped airborne surveys. The surface used in the modelling of terrain effect at each datum is discretized automatically to the largest cell size that will yield the desired accuracy, resulting in much faster modelling than full-resolution calculations. The largest cell sizes within the model occur in areas of minimal correction and at large distances away from the data location. We show synthetic and field examples for proof of concept. The adaptive quadtree method reduces the computational cost of the field example by performing 99.7% fewer calculations than the full model would require while retaining an accuracy of one Eötvös for the gradient data.