Landslides Triggered by the 2020 Qiaojia Mw5.1 Earthquake, Yunnan, China: Distribution, Influence Factors and Tectonic Significance

Journal of Earth Science - Tập 32 - Trang 1056-1068 - 2021
Xiangli He1,2, Chong Xu1,2, Wenwen Qi1,2, Yuandong Huang3, Jia Cheng1, Xiwei Xu1, Qi Yao4, Yongkun Lu5, Boyang Dai5
1National Institute of Natural Hazards, Ministry of Emergency Management of China, Beijing, China
2Key Laboratory of Compound and Chained Natural Hazards Dynamics (Under Construction), Ministry of Emergency Management of China, Beijing, China
3China University of Geosciences, Beijing, China
4China Earthquake Networks Center, Beijing, China
5Yunnan Earthquake Agency, Kunming, China

Tóm tắt

On May 18, 2020, an Mw5.1 earthquake occurred in Qiaojia County, Yunnan Province, China. This moderate-sized event triggered massive coseismic landslides, resulting in some damage. In this work, through visual interpretation of high-resolution (0.8–2 m) Gaofen satellite images before and after the earthquake, 167 landslides were delineated, 18 of which were inspected in the field. Using the landslide number density (LND) and landslide area percentage (LAP), we characterized the spatial distribution of these landslides, and analyzed their possible influence factors and tectonic significance. The results show that these landslides are distributed mostly in the NW-SE direction, roughly parallel to the long axis of seismic intensity zones and the strike of the Xiaohe-Baogunao fault (XBF). The LND and LAP decrease with increasing distances to the fault and from the epicenter to fault ends of the XBF. These permit to suggest that the seismogenic fault of the Qiaojia earthquake is likely a hidden branch of the XBF. All of the landslides induced by this event occurred in the region with the seismic intensity of six degrees or greater of the 2014 Mw6.2 Ludian earthquake. Therefore, it was inferred that the 2020 Qiaojia earthquake was probably the subsequent release of accumulated elastic strain after the 2014 Ludian earthquake in a same tectonic stress regime.

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