Gravity gradient inversions using unstructured tetrahedral meshes

Tycholiz, Cassandra Jo-ann (2013) Gravity gradient inversions using unstructured tetrahedral meshes. Masters thesis, Memorial University of Newfoundland.

[English] PDF - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Download (57MB)

Abstract

Airborne gravity gradiometry is a rapidly growing field. The method is a multicomponent technique that measures the spatial rate of change in the Earth's gravitational field. A limited number of inversion programs exist to provide an interpretation of the gravity gradient data and these programs rely on the use of rectilinear meshes. The objective of this project was to use unstructured tetrahedral meshes to recover the three dimensional distribution of the subsurface density contrast. The inversions were subject to a variety of geological constraints and different gravity gradient tensor component combinations. The results indicate that adding geological constraints improves the recovered density contrast models. The advantage of using an unstructured tetrahedral mesh over a rectilinear mesh is that surfaces from three dimensional geological Earth models can be directly incorporated as geological constraints to further refine recovered models. The results also indicate that incorporating additional gravity gradient components into the inversion improves the density contrast model by better defining the size and depth extent of the geologic units. The differences between the inversion models using single versus multiple components were less apparent as more geological constraints were added.

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