Exact gravity field for polyhedrons with polynomial density contrasts of arbitrary orders

TL;DR

This paper introduces analytical, singularity-free formulas for accurately computing the gravity field of polyhedral bodies with arbitrary polynomial density contrasts, advancing geophysical imaging techniques.

Contribution

It provides the first complete analytical solutions for gravity fields of polyhedrons with polynomial density contrasts of arbitrary order, including variable densities.

Findings

High accuracy verified with synthetic models

Solutions are singularity-free and versatile

First comprehensive analytical approach for such gravity problems

Abstract

Computing gravity field of a mass body is a core routine to image anomalous density structures in the Earth. In this study, we report the existence of analytical routines to accurately compute the gravity potential and gravity field of a general polyhedral mass body. The density contrasts in the polyhedral body can be general polynomial functions up to arbitrary non-negative orders and also can vary in both horizontal and vertical directions. The newly derived analytical expressions of gravity fields are also singularity-free which means that observation sites can have arbitrary geometric relationships with polyhedral mass bodies. One synthetic prismatic body with different density contrasts is used to verify the accuracies of our new closed-form solutions. Excellent agreements are obtained among our solutions and other published solutions. Our work is the first-of-its kind to completely answer the fundamental question on existence of analytic solutions of gravitational field for general mass bodies. It may put an end of searching closed-form solutions in gravity surveying.