Fast, Accurate, and Robust Terrain Corrections using Curvature-Based Resolution Refinement and the Right-Rectangular Prism Method
Title: Fast, Accurate, and Robust Terrain Corrections using Curvature-Based Resolution Refinement and the Right-Rectangular Prism Method
Student: Aaron Price
Advisors: Drs. Glenn Kroeger (Geosciences) and Hoa Nguyen (Mathematics)
Abstract: Some geophysical surveys use variations in local gravitational acceleration to draw conclusions about shape, structure, and density of subterranean masses in the study-area. The local terrain's effect on gravity is known as the terrain correction, and must be calculated accurately for subsurface bodies to be better modeled. Terrain corrections require a precise model of topography such as a Digital Elevation Model (DEM). The gravitational effect of topographical protrusions and depressions defined by the DEM can be found explicitly by integrating the law of universal gravitation over bounds defined by the topographic model, or by approximating this integral. The terrain correction has traditionally been difficult and time-consuming to compute, even with the aid of a computer. Here I expand on the method of using right rectangular prisms to approximate the gravitational effect of terrain. I define an algorithm that uses coarser- or finer-resolution elevation data to minimize computation time while maintaining accuracy. The algorithm is easily integrated into ArcGIS, an industry-standard application. Additionally, the algorithm is adaptable to forward and inverse modeling of density bodies.