The Quantification of Fracture Patterns

Fractures in deformed rocks are rarely uniform or random. Fracture orientations, sizes, shapes and spatial distributions often exhibit some kind of order, or pattern. In detail, there may be relationships among the different fracture attributes e.g. small fractures dominated by one orientation, larger fractures by another. This is important because the mechanical (e.g. strength, anisotropy) and transport (e.g. fluids, heat) properties of rock depend on these fracture patterns and fracture attribute relationships. This presentation describes a methodology to quantify fracture patterns, including distributions in the fracture attributes and their spatial variation. There is a large body of published work on the quantification of relatively simple joint patterns, but fault zones present a bigger, and arguably more important, challenge. The method presented is inherently scale independent, and a key task will be to analyse, interpret and integrate quantitative fracture pattern data from micro- to macro-scales.