How Does Thermal Pressurization of Pore Fluids Affect 3D Strike-Slip Earthquake Dynamics and Ground Motions?

Jagdish Chandra Vyas, Alice-Agnes Gabriel, Thomas Ulrich, Paul Martin Mai, Jean-Paul Ampuero

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Frictional heating during earthquake rupture raises the fault-zone fluid pressure, which affects dynamic rupture and seismic radiation. Here, we investigate two key parameters governing thermal pressurization of pore fluids – hydraulic diffusivity and shear-zone half-width – and their effects on earthquake rupture dynamics, kinematic source properties, and ground motions. We conduct 3D strike-slip dynamic rupture simulations assuming a rate-and-state dependent friction law with strong velocity weakening coupled to thermal-pressurization of pore fluids. Dynamic rupture evolution and ground shaking are densely evaluated across the fault and Earth’s surface to analyze the variations of rupture parameters (slip, peak slip rate, rupture speed, and rise time), correlations among rupture parameters, and variability of peak ground velocity. Our simulations reveal how variations in thermal-pressurization affect earthquake rupture properties. We find that the mean slip and rise time decrease with increasing hydraulic diffusivity, whereas mean rupture speed and peak slip-rate remain almost constant. Mean slip, peak slip-rate, and rupture speed decrease with increasing shear-zone half-width, whereas mean rise time increases. Shear-zone half-width distinctly affects the correlation between rupture parameters, especially for parameter pairs (slip, rupture speed), (peak slip-rate, rupture speed), and (rupture speed, rise time). Hydraulic diffusivity has negligible effects on these correlations. Variations in shear-zone half-width primarily impact rupture speed, which then may affect other rupture parameters. We find a negative correlation between slip and peak slip-rate, unlike simpler dynamic rupture models. Mean peak ground velocities decrease faster with increasing shear-zone half-width than with increasing hydraulic diffusivity, whereas ground-motion variability is similarly affected by both the parameters. Our results show that shear-zone half-width affects rupture dynamics, kinematic rupture properties, and ground shaking more strongly than hydraulic diffusivity. We interpret the importance of shear-zone half-width based on the characteristic time of diffusion. Our findings may inform pseudodynamic rupture generators and guide future studies on how to account for thermal-pressurization effects.
Original languageEnglish (US)
JournalBulletin of the Seismological Society of America
DOIs
StatePublished - May 10 2023

Bibliographical note

KAUST Repository Item: Exported on 2023-05-19
Acknowledged KAUST grant number(s): BAS/1/1339-01-01, URF/1/3389-01-01
Acknowledgements: The authors acknowledge the work of and helpful discussions with Stephanie Wollherr, Sebastian Anger, and Kadek Palgunadi on the thermal pressurization (TP) implementation in SeisSol. The authors also thank Michael Barall and Yongfei Wang for uploading their solutions to the TPV105-3D benchmark exercise to the Southern California Earthquake Center (SCEC) platform. The research presented in this article is supported by the King Abdullah University of Science and Technology (KAUST) in Thuwal, Saudi Arabia, under Grant Numbers BAS/1/1339-01-01 and URF/1/3389-01-01 (Jagdish Chandra Vyas and Paul Martin Mai). Alice-Agnes Gabriel and Thomas Ulrich acknowledge the support of the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (ERC Starting Grant TEAR, Grant Agreement Number 852992), Horizon Europe (ChEESE-2P Grant Number 101093038, DT-GEO Grant Number 101058129, and Geo-INQUIRE Grant Number 101058518), the SCEC (Grant Number 22135), the National Science Foundation (NSF, Grant Number EAR-2121666), the National Aeronautics and Space Administration (NASA, Grant Number 80NSSC20K0495), and the Bavarian State Ministry for Science and Art in the framework of the project Geothermal-Alliance Bavaria. Jean-Paul Ampeuro acknowledges the support of the French government through the Investments in the Future project UCAJEDI (ANR-15-IDEX-01) managed by the French National Research Agency (ANR). Earthquake rupture dynamics and ground-motion modeling have been carried out using the KAUST Supercomputing Laboratory (KSL), and the authors acknowledge the support of the KSL staff. The authors also thank Kadek Palgunadi and the SeisSol software team (https://seissol.org/, last accessed April 2023) for their support during the software installation.

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics

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