Gravity survey at Siġġiewi

Abstract

A gravity survey is a geophysical tool involving the measurements of variations in the Earth's Gravitational field in order to model the subsurface geology. This technique finds its uses in mineral exploration, environmental studies and engineering investigations. This dissertation reviews the technique, instrumentation, procedures and presents a case study in the Southern part of Malta. Accurate measurements of the gravitational field were taken at nineteen stations, including the base station, laid evenly along a profile from Luqa to Għar Lapsi. The measurements taken were reduced and processed to the base station datum, and corrections were done in order to remove the effects of instrumental drift, topography, latitude, elevation or free-air and Bouguer. The resulting gravity anomaly was compared to those of various models based on the rectangular prism until an acceptable fit was obtained. The models were restrained by the surface geology of the area. The survey was able to model a subsurface structure characterized by a pronounced fault separating sedimentary formations of different density contrasts.