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Fault structure and slip mechanics of the 2022 Mw 6.7 Menyuan earthquake revealed by coseismic rupture observations

Lookup NU author(s): Dr Chuang Song

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This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).


Abstract

© 2023 The Authors. Large and shallow strike-slip earthquakes produce striking ground ruptures, damaging roads and infrastructure but providing great opportunities for examining the fault's structure. After the 2022 Mw 6.7 Menyuan earthquake, we observed abundant surface fractures by a combination of optical remote sensing, radar offset and unmanned aerial vehicle measurements. These fractures reveal a complex fault structure including apparent bending geometries and bifurcating branches, which are essential to understanding the mechanisms of faulting. In this paper, we used triangular dislocations to construct the fault geometry that reflected the distribution of measured strike changes but avoided unexcepted discontinuities and overlaps where the fault bent. The modeled fault geometry revealed an extensional releasing bend which was responsible for the southward branching of the fault rupture at its western edge. Our results also demonstrated the potential to explain the occurrence of aftershock clusters and to infer their fault geometries through the correlation analysis of the aftershock distribution and the slip induced stress field. The triangular dislocation model also enabled the calculation of the fault plane roughness and its spatial variation which directly controlled the fault slip magnitude and rupture termination. These analyses reveal an unprecedented level of detail of the fault structure and slip mechanics and, to some extent, offer insights into the physical processes and structural properties of crustal faults in the Earth's shallow crust.


Publication metadata

Author(s): Yu C, Li Z, Song C, Han B, Chen B, Li X, Peng J

Publication type: Article

Publication status: Published

Journal: Tectonophysics

Year: 2024

Volume: 872

Print publication date: 09/02/2024

Online publication date: 29/12/2023

Acceptance date: 20/12/2023

Date deposited: 24/01/2024

ISSN (print): 0040-1951

Publisher: Elsevier BV

URL: https://doi.org/10.1016/j.tecto.2023.230192

DOI: 10.1016/j.tecto.2023.230192

Data Access Statement: The Sentiel-1 interferograms and offsets, surface fractures identified by GF-7 and UAV, fault surface lines, and the fault slip model in the study are available at Harvard Dataverse via https://doi.org/10.7910/DVN/TAEHK1 licensed under CC01.0 (public domain).


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Funding

Funder referenceFunder name
2021TD-51
300102261108
300102262902
300102263401
41941019
300102260301
300203211261
Fundamental Research Funds for the Central Universities, CHD
National Natural Science Foundation of China
Shaanxi Province Geoscience Big Data and Geohazard Prevention Innovation Team
Shaanxi Province Science and Technology Innovation team

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