Effects of Failure Parameterization on Pre- and Co-Seismic Earthquake Rupture
Description:
Different physical processes accommodating fault failure during an earthquake rupture affect how the shear stress along the fault evolves with fault slip – the failure parameterization used in earthquake models. We investigate different failure parameterizations (failure laws) to determine how the shapes of the laws and their parameters affect earthquake nucleation and the coseismic phase of the earthquake rupture. We use the 2D finite element method and perform quasi-static simulations to study the implications of these different parameterizations for the slip amount, slip rate, and timing of the earthquake nucleation phase. We use dynamic simulations to address the specifics of rupture propagation during the coseismic phase. Failure laws studied include slip-weakening friction, exponential cohesive zone law, parabolic cohesive zone law, and several poly-linear failure laws. We use fracture energy and other common failure law parameters for quantitative comparison. From the quasi-static models and the initial phase of the dynamic models we find that different failure laws play a significant role in the duration of the earthquake nucleation phase, the amount of accumulated preseismic slip and the lateral slip propagation. The later stages of the dynamic rupture models show Lorentz contraction of the process zone, which results in almost indistinguishable dynamic ruptures with almost identical far field observables: source-time functions and spectra. This result confirms the validity of the small-scale yield approximation (i.e., process zone details can be ignored and the rupture propagation is governed by the fracture energy magnitude) for sufficiently fast ruptures.
Session: Earthquake Source Parameters: Theory, Observations and Interpretations
Type: Oral
Date: 4/18/2023
Presentation Time: 10:30 AM (local time)
Presenting Author: Ekaterina Bolotskaya
Student Presenter: No
Invited Presentation:
Authors
Ekaterina Bolotskaya Presenting Author Corresponding Author bolee@mit.edu Massachusetts Institute of Technology |
Bradford Hager bhhager@mit.edu Massachusetts Institute of Technology |
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Effects of Failure Parameterization on Pre- and Co-Seismic Earthquake Rupture
Category
General Session