Using network analyses within geographic information system technologies to quantify geometries of shear zone networks

Abstract

Shear zones often exhibit anastomosing network geometries. Previous work has shown that the detailed geometries of shear zone networks may partially control strain localization, fluid flow, rheology, and deformation mechanisms. However, there are currently no reliable tools to quantify network geometries such as the distribution of individual small shear zones and the connectedness of the network. Geographic information systems (GIS) provide a potential method for quantifying network geometries. GIS-based networking analyses have been used to quantify many different types of other networks, and here they are applied to shear zones. Many parameters within GIS-based networking analyses are useful for quantifying shear zone network geometries, including the connectivity parameters gamma and alpha, sinuosity, and vertex distribution patterns. Sets of these parameters are useful to quantitatively distinguish geometrical patterns of shear zone networks over a variety of conditions. Further quantification of shear zone network geometries may allow us to link those geometries to shear zone mechanisms, strain accumulation, and rheology.