GEOMECHANICAL SENSITIVITIES OF INJECTION-INDUCED EARTHQUAKES: IMPLICATIONS FOR CRUSTAL PERMEABILITY?

Wastewater injection across the U.S. mid-continent has induced thousands of earthquakes over the past decade in relatively quiescent geologic regions. In Oklahoma and Kansas, the response of faults in the crystalline basement to wastewater injection is governed by both hydrogeologic and geomechanical parameters. Here, I’ll discuss how large-scale variations in the seismic response to injection in Oklahoma and Kansas may be explained by variation in regional geomechanical properties. Stochastic geomechanical models show that properties such as stress state can modulate the availability of critically stressed fractures and faults, which are the primary pathways for fluid flow in the low-permeability, crystalline basement. The modulation of geomechanical parameters may have implications for bulk-scale crustal permeability.