The role of fracture branching in the evolution of fracture networks: An outcrop study of the Jurassic Navajo Sandstone, southern Utah

Fractures strongly influence the permeability of geologic formations, and because most fractures in subsurface are below resolution geophysical methods, predicting spatial evolution fracture networks is important for groundwater resources, oil gas production, geothermal energy. Previous researchers have established that variations lithologic mechanical properties propagation joints layered rocks under stable stress conditions, but few studies addressed how instabilities local fields, conjunction with rock properties, lead to branching. We investigate NE-striking footwall west-dipping Sevier fault Utah, USA, where canyons expose sub-horizontal Jurassic Navajo Sandstone. analyzed field data, petrographic unmanned-aerial-vehicle (UAV) imagery document network. also used structure-from-motion (SfM) software build a 3D virtual outcrop model, measuring 100 m high 260 wide, aid our analysis network geometry, intensity, spacing variations. Data reveal an up-section increase intensity decrease regularity partly accommodated by upward suggest branching was initiated combination changes behavior within cross-bed sets twist hackle associated mixed mode systems. These tree-like geometries may be high-velocity, earthquake-related events. Fracture influences should considered investigating development