Aseismic strain localization prior to failure and associated seismicity in crystalline rock.

Recent laboratory tests and large-scale observations have revealed the complex interplays between aseismic and seismic deformation, as well as the progressive localization of the rock failure process. To investigate these processes, we conducted triaxial tests that combined distributed strain sensing (DSS) with acoustic emission (AE) sensors. Progressive strain localization was detected by DSS at 80% of the peak stress but did not produce measurable AEs.

Pre-Failure Strain Localization in Siliclastic Rocks: A Comparative Study of Laboratory and Numerical Approaches.

We combined novel laboratory techniques and numerical modeling to investigate (a)seismic preparatory processes associated with deformation localization during a triaxial failure test on a dry sample of Berea sandstone. Laboratory observations were quantified by measuring strain localization on the sample surface with a distributed strain sensing (DSS) array, utilizing optical fibers, in conjunction with both passive and active acoustic emission (AE) techniques. A physics-based computational model was subsequently employed to understand the underlying physics of these observations and to establish a spatio-temporal correlation between the laboratory and modeling results.

Inversion in the permeability evolution of deforming Westerly granite near the brittle-ductile transition.

Fluid flow through crustal rocks is controlled by permeability. Underground fluid flow is crucial in many geotechnical endeavors, such as CO sequestration, geothermal energy, and oil and gas recovery. Pervasive fluid flow and pore fluid pressure control the strength of a rock and affect seismicity in tectonic and geotechnical settings.