Exploration Geophysics Exploration Geophysics Society
Journal of the Australian Society of Exploration Geophysicists

Just Accepted

This article has been peer reviewed and accepted for publication. It is in production and has not been edited, so may differ from the final published form.

Quantifying the differences between gravity reduction techniques

Philip Heath

Abstract

Gravity data processing (reduction) generally utilises the best-available formulae at the time. New and improved formulae have been introduced over time and the resulting newly processed gravity will not match the old. Additionally, mistakes made in the gravity reduction process, as well as the incompatibilities between various equations, will inevitably lead to errors in the final product. This can mean that overlapping gravity surveys are often incompatible, and can lead to incorrect geological interpretations. In this paper I demonstrate the magnitude of the resulting change when different information is introduced at various stages of the gravity reduction process. I have focussed on differences relating to calibration factors, time zones and time changes, height, geodetic datums, gravity datums, and the equations involved therein. The differences range from below the level of detection (0.01mGal), to over 17.0 mGal. The results highlight the need to not only be diligent and thorough in processing gravity data, but also how it is necessary to document the steps taken when processing data. Without properly documented gravity surveys they cannot be reprocessed should an error be identified.

EG17094  Accepted 05 October 2017

© ASEG 2017