Revising Gravity Terrain Corrections in Tasmania

Abstract

Terrain corrections for determination of the complete Bouguer anomaly are empirically evaluated with respect to a number of different techniques, parameters and digital terrain model data sets, for areas in western and northern Tasmania.

For the most part, while terrain corrections calculated from very high resolution terrain models (1.2 metres or better) are presumed to deliver the most accurate results, those computed for the same area using only a Statewide 25 metre-cell digital terrain model to within two metres of gravity stations correspond remarkably well. Internally consistent comprehensive terrain correction of acceptable yet maximal accuracy can therefore be calculated for all Tasmanian gravity stations, even if very high resolution DTMs are unavailable.

Fully automatic terrain correction computation from two metres to 167 kilometres from gravity stations will result in significantly improved removal of topographic effects over extant manual corrections, which were limited to 22 kilometres.