Wang, S, Nissen, E, Pousse-Beltran, L et al. (3 more authors) (2022) Structural controls on Coseismic rupture revealed by the 2020 Mw 6.0 Jiashi earthquake (Kepingtag belt, SW Tien Shan, China). Geophysical Journal International. ggac159. ISSN 0956-540X
Abstract
The Kepingtag (Kalpin) fold-and-thrust belt of the southern Chinese Tian Shan is characterized by active shortening and intense seismic activity. Geological cross-sections and seismic reflection profiles suggest thin-skinned, northward-dipping thrust sheets detached in an Upper Cambrian décollement. The January 19 2020 Mw 6.0 Jiashi earthquake provides an opportunity to investigate how coseismic deformation is accommodated in this structural setting. Coseismic surface deformation resolved with Sentinel-1 Interferometric Synthetic Aperture Radar (InSAR) is centered on the back limb of the frontal Kepingtag anticline. Elastic dislocation modelling suggests that the causative fault is located at ∼7 km depth and dips ∼7○ northward, consistent with the inferred position of the décollement. Our calibrated relocation of the mainshock hypocenter is consistent with eastward, unilateral rupture of this fault. The narrow slip pattern (length ∼37 km but width only ∼9 km) implies that there is a strong structural or lithological control on the rupture extent, with up-dip slip propagation possibly halted by an abrupt change in dip angle where the Kepingtag thrust is inferred to branch off the décollement. A depth discrepancy between mainshock slip constrained by InSAR and teleseismic waveform modelling (∼7 km) and well-relocated aftershocks (∼10–20 km) may suggest that faults within sediments above the décollement exhibit velocity-strengthening friction.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2022, Oxford University Press. This is an author produced version of an article, published in Geophysical Journal International. Uploaded in accordance with the publisher's self-archiving policy. |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Inst of Geophysics and Tectonics (IGT) (Leeds) |
Funding Information: | Funder Grant number Royal Society URF\R1\180088 Royal Society RF\ERE\210041 |
Depositing User: | Symplectic Publications |
Date Deposited: | 25 Apr 2022 10:32 |
Last Modified: | 25 Apr 2022 10:32 |
Status: | Published online |
Publisher: | Oxford University Press |
Identification Number: | 10.1093/gji/ggac159 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:185961 |