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Fault gouge failure induced by fluid injection: Hysteresis, delay and shear-strengthening by Sarma, Pritom; Aharonov, Einat; Toussaint, Renaud; Parez, Stanislav is a scholarly article available to read on EtoBox.

What is Fault gouge failure induced by fluid injection: Hysteresis, delay and shear-strengthening about?

Natural faults often contain a fluid-saturated, granular fault-gouge layer, whose failure and sliding processes play a central role in earthquake dynamics. Using a two-dimensional discrete element model coupled with fluid dynamics, we simulate a fluid-saturated granular layer, where fluid pressure is incrementally raised. At a critical fluid pressure level, the layer fails and begins to accelerate. When we gradually reduce fluid pressure, a distinct behavior emerges: slip-rate decreases linearly until the layer halts at a fluid pressure level below that required to initiate failure. During this pressure cycle the system exhibits (1) velocity-strengthening friction and (2) frictional hysteresis. These behaviors, well established in dry granular media, are shown to extend here to shear of dense fluid-saturated granular layers. Additionally, we observe a delay between fluid pressure increase and failure, associated with pre-failure dilative strain and "dilational-hardening". During the delay period, small, arrested slip events dilate the layer in preparation for full-scale failure. Our findings may explain (i) fault motion that continues even after fluid pressure returns to pre-inject

Author

Sarma, Pritom; Aharonov, Einat; Toussaint, Renaud; Parez, Stanislav

Published

2024

Language

EN