Surface ruptures of the 2022 Guanshan-Chihshang earthquakes in central Longitudinal Valley area, eastern Taiwan

Autor: Yu Wang, Sheng-Han Wu, Hoi Ling Birdie Chou, Yi-Yu Li, Wai San Cheng, Andrew Ho, Jian-Ming Chen, Sze-Chieh Liu, Chia-Yun Hsieh, Siang Duan, Saw Myat Min, Ei Mhone Nathar Myo, Yuan-Lu Tsai, Nai-Wun Liang, Jhih-Hao Liao, Tsz Yau Amundsen Lam, En-Wei Chang, J. Bruce H. Shyu
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Terrestrial, Atmospheric and Oceanic Sciences, Vol 35, Iss 1, Pp 1-25 (2024)
Druh dokumentu: article
ISSN: 1017-0839
2311-7680
DOI: 10.1007/s44195-024-00077-3
Popis: Abstract The Mw 6.4 and 6.8 Guanshan-Chihshang earthquakes occurred on 17 and 18 September 2022 resulted in prominent surface ruptures within the Longitudinal Valley in eastern Taiwan, particularly along the Yuli fault. Approximately 18 h after the mainshock, we began to document the surface rupture near Yuli Town. Our result suggests the surface rupture formed a confined single left-lateral trace in the town of Yuli, characterized by a series of en échelon right-stepping left-lateral faulting geometry. The rupture of 2022 roughly matches the locations of 1951 surface ruptures inside Yuli Town, with a similar amount of left-lateral cross-fault displacement. North and South of the Yuli residential area, we identified several sections of the surface rupture distributed in the water-saturated paddy fields. The maximum left-lateral displacement recorded across the rupture can reach 1.4 m just south of Yuli, with the fault scarp resembling a high-angle west-dipping fault geometry. In addition to the co-seismic surface ruptures, our repeating cross-fault measurements show significant post-seismic shallow after-slip along the Yuli fault. The amount of post-seismic deformation within 3 months after the mainshock is close to, or even higher than the co-seismic cross-fault displacement, consistent with local witness accounts and post-event field photos which showed continuous damage and displacement of building floors and roads after the earthquake. Such shallow post-seismic slips were also observed along the main fault trace in the 2014 South Napa earthquake, and likely represent the shallow elastoplastic behavior of the sub-vertical fault in the young alluvial sediments.
Databáze: Directory of Open Access Journals
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