Tectonophysics2022，Vol.82716.DOI:10.1016/j.tecto.2022.229275

Coseismic surface ruptures, slip distribution, and 3D seismogenic fault for the 2021 Mw 7.3 Maduo earthquake, central Tibetan Plateau, and its tectonic implications

Ren, Junjie Xu, Xiwei Zhang, Guangwei Wang, Qixin Gai, Hailong Kang, Wenjun Zhang, Zhiwen
Tectonophysics2022，Vol.82716.DOI:10.1016/j.tecto.2022.229275
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  • NSTL
  • Elsevier

Coseismic surface ruptures, slip distribution, and 3D seismogenic fault for the 2021 Mw 7.3 Maduo earthquake, central Tibetan Plateau, and its tectonic implications

Ren, Junjie 1Xu, Xiwei 1Zhang, Guangwei 1Wang, Qixin 1Gai, Hailong 2Kang, Wenjun 1Zhang, Zhiwen1
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作者信息

  • 1. Minist Emergency Management China MEMC
  • 2. Qinghai Earthquake Agcy
  • 折叠

Abstract

The 2021 Mw 7.3 Maduo earthquake, which hit the high mountain area of the internal Bayan Har Block in the central Tibetan Plateau, generated a similar to 154 km-long, nearly E-W-striking surface rupture zone. Field observations indicate prominent surface breaks characterized by discontinuous shear faults, en echelon tensional fissures, and mole track structures, revealing a dominantly left-lateral strike-slip motion with a maximum sinistral offset of similar to 2.7-2.8 m and general offset of similar to 1.0-1.5 m. The west part of the Maduo surface rupture zone occurred along the pre-existing Jiangcuo fault. Its east portion cut through some WNW-trending tectonics, indicating a previously unknown fault. The epicenter and slip distribution show a bilateral rupture for the Maduo quake. The complex 3D geometry of the Maduo seismogenic fault has controlled the occurrence of aftershocks and the multimodal distribution of coseismic displacements. The abnormally long Maduo surface rupture zone suggests that the rupture area-magnitude relationship might be more applicable than the rupture length-magnitude relationship for the magnitude estimation of a paleo-event. The occurrence of the Maduo earthquake challenges the active block model which used to predict little or no slip partitioning and large earthquakes in the block interior. A reappraisal of seismic hazard along intra-block faults with low strain rates is needed, especially across densely populated regions.

Key words

Maduo earthquake/Coseismic surface rupture/Slip distribution/3D seismogenic fault/Tibetan Plateau/Intra-block fault/ALTYN TAGH FAULT/KUNLUN FAULT/EASTERN TERMINATION/YUTIAN EARTHQUAKE/ACTIVE TECTONICS/XIANSHUIHE FAULT/OBLIQUE-SLIP/RECURRENCE/MAGNITUDE/RATES

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出版年

2022
Tectonophysics

Tectonophysics

EISCI
ISSN：0040-1951
被引量13
参考文献量90
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