WITHDRAWN: Modeling Rupture Propagation Into Creeping Faults by Thermal Pressurization
Description:
Different sections of faults, like the San Andreas (SAF), accommodate stress via stick-slip under velocity-weakening friction or through gradual creep in a velocity-strengthening regime. When a rupture reaches a region of slow slip, thermal pressurization of pore fluids can enable rapid weakening and dynamic failure of the creeping zone (Noda and Lapusta, Nature, 2013). We explore whether a theoretical Mw 7 earthquake, which propagates towards the creeping section, could generate enough thermal pressurization to rupture through the creeping section, building upon recent observations that the creeping section of the SAF may have experienced large seismic slip (Coffey et al., Geology, 2022). At the same time, the 2004 Mw 6 Parkfield earthquake did not significantly propagate into the creeping section. The highly simplified model of the simulated fault consists of locked and creeping segments, depth-averaged to consider only variations with its length and embedded within a 2-D linearly elastic isotropic medium. The fault is governed by a logarithmic rate-and-state friction law with thermal pressurization of pore fluids due to shear heating, with the diffusion of heat and fluids from the fault. We vary three thermal pressurization parameters (the coupling coefficient between temperature and pore pressure change, hydraulic diffusivity, and half-width of the actively shearing layer) and the effect of the off-fault inelasticity to find the combinations that lead to dynamic rupture through the creeping region when the event size is large enough. Our preliminary results indicate that there are indeed plausible parameter combinations for which Mw 6 events arrest, but Mw 7 events dynamically rupture the creeping segment. We will report on our current exploration of the fuller parameter space and ways of explaining the simulation results with theoretical considerations.
Session: Characteristics and Mechanics of Fault Zone Rupture Processes, from Micro to Macro Scales - I
Type: Oral
Date: 5/2/2024
Presentation Time: 08:15 AM (local time)
Presenting Author: Victor
Student Presenter: Yes
Invited Presentation:
Authors
Oliver Stephenson oliver.stephenson@caltech.edu California Institute of Technology |
Victor Vescu Presenting Author Corresponding Author vvescu@caltech.edu California Institute of Technology |
Nadia Lapusta lapusta@caltech.edu California Institute of Technology |
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WITHDRAWN: Modeling Rupture Propagation Into Creeping Faults by Thermal Pressurization
Category
Characteristics and Mechanics of Fault Zone Rupture Processes, from Micro to Macro Scales