Gongola Basin Geoid Determination using Isostatic Models and Seismic Reflection Data and Geophysical Interpretation

摘要

The application of Stokes’ formula to create geoid undulation requires no masses outside the geoid. Usually, a constant density of 2.67 g/cm3 is used in the determination of the geoid which introduces error in the reduced gravity anomalies (Helmert’s condensation) and consequently the geoid. In this paper, isostatic models of Airy—Heiskanen and Pratt—Hayford were utilized in the determination of the geoid by considering the planar and spherical approximation models the indirect effect of the topographic lateral density variation on the geoid was computed as additive correction for the improvement of the accuracy of the computed geoid. Additional density information deduced from seismic and well log information were considered for the variable density computation. The geopotential geoid undulations were computed from the EGM 2008 model. The residual geoid was obtained by subtracting the local isostatic geoid from the geopential geoid. Geoid and gravity admittance studies were also carried out to complement the results from the residual geoid.