Cross-diffusion waves resulting from multiscale, multiphysics instabilities: application to earthquakes
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se-12-1829-2021.pdf
Description
Published version
Size
4.3 MB
Format
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Checksum (MD5)
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Author(s)
Regenauer-Lieb, Klaus
Hu, Manman
Schrank, Christoph
Chen, Xiao
Clavijo, Santiago Peña
Kelka, Ulrich
Karrech, Ali
Gaede, Oliver
Blach, Tomasz
Roshan, Hamid
Date Issued
August 16, 2021
Journal
Solid Earth
Publisher
Copernicus GmbH
Citation
Regenauer-Lieb, K., Hu, M., Schrank, C., Chen, X., Clavijo, S. P., Kelka, U., Karrech, A., Gaede, O., Blach, T., Roshan, H., Jacquey, A. B., Szymczak, P., and Sun, Q.: Cross-diffusion waves resulting from multiscale, multiphysics instabilities: application to earthquakes, Solid Earth, 12, 1829–1849.
Version
Final published version
Abstract
Theoretical approaches to earthquake instabilities propose shear-dominated source mechanisms. Here we take a fresh look at the role of possible volumetric instabilities preceding a shear instability. We investigate the phenomena that may prepare earthquake instabilities using the coupling of thermo-hydro-mechano-chemical reaction–diffusion equations in a THMC diffusion matrix. We show that the off-diagonal cross-diffusivities can give rise to a new class of waves known as cross-diffusion or quasi-soliton waves. Their unique property is that for critical conditions cross-diffusion waves can funnel wave energy into a stationary wave focus from large to small scale. We show that the rich solution space of the reaction–cross-diffusion approach to earthquake instabilities can recover classical Turing instabilities (periodic in space instabilities), Hopf bifurcations (spring-slider-like earthquake models), and a new class of quasi-soliton waves. Only the quasi-soliton waves can lead to extreme focussing of the wave energy into short-wavelength instabilities of short duration. The equivalent extreme event in ocean waves and optical fibres leads to the appearance of “rogue waves” and high energy pulses of light in photonics. In the context of hydromechanical coupling, a rogue wave would appear as a sudden fluid pressure spike. This spike is likely to cause unstable slip on a pre-existing (near-critically stressed) fault acting as a trigger for the ultimate (shear) seismic moment release.
MIT Department
Massachusetts Institute of Technology. Department of Civil and Environmental Engineering
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Creative Commons Attribution
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DOI of Published Version
https://doi.org/10.5194/se-12-1829-2021
