Estimating three-dimensional rock discontinuity orientation from digital images of fracture traces

This paper describes a computer approach that has been developed for estimating three-dimensional fracture orientations from two-dimensional fracture trace information gathered from digital images of exposed rockfaces. The approach assumes that the fractures occur in sets, and that each set can be described by a mean orientation and a measure of the scatter about the mean. Mathematical relationships are developed that relate the 3D fracture properties with the trace angles that would be measured on one or more rockfaces. These algorithms are used in conjunction with a genetic algorithm to invert the trace angles to estimate 3D joint orientation. A number of case studies have been conducted indicating a great potential for the technique.