2024-03-29T08:09:45Z
https://nagoya.repo.nii.ac.jp/oai
oai:nagoya.repo.nii.ac.jp:00027195
2023-01-16T05:03:58Z
1908:1909:1910
Intraplate Strike-Slip Faulting, Stress Accumulation, and Shear Localization of a Crust-Upper Mantle System With Nonlinear Viscoelastic Material
Zhang, Xuelei
Sagiya, Takeshi
open access
© 2018 American Geophysical Union
earthquake cycle
nonlinear Maxwell rheology
plastic shear zone evolution
We investigate the evolution of tectonic background stress and elastic as well as inelastic strain in a crust‐upper mantle system around an infinitely long vertical strike‐slip fault in a self‐consistent mechanical earthquake cycle model. In the early stage of the stress evolution, deformation of the crust and the upper mantle is dominated by a uniform simple shear. Shear localization in the lower crust starts when coseismic rupture extends to the entire brittle upper crust. Together with this transition, the earthquake recurrence intervals decrease by an order of magnitude due to a basal drag originated from a localized plastic flow of the lower crust. After the shear zone is fully developed in the lower crust, the fault slip rate catches up with the far‐field velocity and earthquakes starts to occur periodically. Such a steady state can be reached in several hundred thousand years from the beginning, which includes few hundreds of earthquake cycles. A shear zone with large cumulative strain needs a few million years to develop under an intraplate strike‐slip fault, which is much longer than the time for shear strain rate to be localized. The model successfully reproduced evolution of tectonic stress around an intraplate strike‐slip fault, interacting with the development of localized shear zone in the lower crust. The model demonstrates the importance of considering the whole mechanical system in which rheological structure and fault activities interacting with each other for the better understanding of the intraplate earthquakes.
ファイル公開:2019-04-01
Wiley
2018-10
eng
journal article
VoR
http://hdl.handle.net/2237/00029394
https://nagoya.repo.nii.ac.jp/records/27195
https://doi.org/10.1029/2018JB016421
2169-9313
2169-9356
Journal of Geophysical Research: Solid Earth
123
10
9269
9285
https://nagoya.repo.nii.ac.jp/record/27195/files/Zhang_et_al-2018-Journal_of_Geophysical_Research__Solid_Earth.pdf
application/pdf
2.8 MB
2019-04-01