Fracture Network Localization Preceding Catastrophic Failure in Triaxial Compression Experiments on Rocks

We quantify the spatial distribution of fracture networks throughout six in situ X-ray tomography triaxial compression experiments on crystalline rocks at confining stresses 5–35 MPa order to how development controls final macroscopic failure rock, a process analogous those that control geohazards such as earthquakes and landslides. Tracking proportion cumulative volume fractures with volumes &amp;gt;90th percentile total volume, ?v90/vtot indicates tend increase localization toward these largest for up 80% applied differential stress. The evolution this metric also matches Gini coefficient, which measures deviation population from uniformity. These results are consistent observations localizing low magnitude seismicity before large southern California. In both analysis present work, phases delocalization interrupt general preceding catastrophic failure, indicating does not necessarily indicate reduction seismic hazard. However, maximum monotonically. Experiments higher stress experience greater localization. To further localization, we compare geometry fractures, percentile, best fit plane through immediately failure. r 2 scores mean distance monzonite than granite. smaller mineral diameter lower granite may contribute result. various metrics reveals close association between yielding acceleration network Near yielding, id="m2"><mml:mstyle coefficient while decreases. Macroscopic thus occurs when rate increases.