Fluid-Thermal Coupled Melt Generation with Regularized Yoffe Functions in Seismogenic Fault Zone

Live Poster Session: Zoom Link
Thursday, July 30th 1:15-2:30pm EDT

Abstract: Pseudotachylite is a friction-induced glassy fine-grained rock observed in exhumed fault zones, and it has become the unequivocal evidence for high slip rate seismic activity in the past. Immediately after the nucleation of an earthquake, the wall rocks along the fault plane accelerates to high slip velocity (~1-10 m/s) producing heat flux over 10^7 watt per square meter at seismogenic depth of ~10 kilometers; such heat progressively melts the wall rock until the rupture arrests. Laboratory high speed rotary experiments have thoroughly examined various mechanical and physical processes yet how frictional melt dynamically affects the kinematic properties of faults is not well understood. Our work integrates the Newtonian rheology of melt layer with a classical two-phase Stefan Problem to numerically simulate the viscous stress drop and melt production under different Yoffe functions. Results indicate that the incipient melt thickness has negligible effect on the maximum thickness of the melt but too thin the layer as adopted by previous workers might potentially viscous braking. Under certain combinations of parameters in Yoffe function, maximum viscous shear stress and stress drop are comparable to the calculations based on the field work. However, the inability to reproduce the melt thickness measured from the sample implies the underestimation of the total slip distance or the effects of lithic fragments on the melt viscosity.

Poster-Summer-@-Wes-Donglai-Yang

Live Poster Session: Zoom Link
Thursday, July 30th 1:15-2:30pm EDT