An Expression for Gravity Generated by an Anomalous Geological Body and Its Application in Bathymetry Inversion

The gravity anomaly and vertical gravity gradient due to anomalous geological bodies are mainly computed by numerical methods, so it is difficult and time-consuming to use the gravity-geological method to invert seafloor topography. This paper addresses this issue by deriving an expression for gravity generated by a cylinder based on a series expansion. The choice of number for terms in the series is estimated by comparing with the numerical method, especially when the depth H=4000m, the accuracy of 1mGal(1Gal=10-2m/s2) can be achieved when the series are 9. The expressions can be used to establish the relationships between the shape of an anomalous body and the generated vertical gravity and vertical gravity gradient, respectively. Finally, the potential applications of the expressions in inverting seafloor topography are illustrated by synthetic examples.