Preliminary analyses of landslides and sand liquefaction triggered by 22 May, 2021, Maduo Mw 7.3 earthquake on Northern Tibetan Plateau, China

During the Maduo Earthquake (MDEq) (M-w, 7.3), which occurred on 22 May 2021 in the northern Tibetan Plateau, coseismic surface ruptures, numerous land liquefaction instances and landslides, were triggered along the NW strike of the similar to 160 km long aftershock zone. We performed three times emergency field surveys (22 May to 3 Jun., 28 Jun. to 14 Jul., 8 24 Oct., 2021) with unmanned aerial vehicle (UAV) orthophoto and digital elevation model (DEM) data. We found a discontinuous coseismic surface rupture zone along with loose sediment, severe sand liquefaction regions with an area of similar to 10(3) km(2) along the Yellow River and its tributaries. More than 23 coseismic landslides had been checked with relative small-size volume for limited local terrain relief. Three of those landslides had relatively small source areas and volumes and affected relatively large areas. We identified numerous tension cracks in and around the trailing edges, which could trigger more landslides in the future. Further detailed research into the occurrence of these three landslides will reveal the failure mechanism of the earthquake (shaking)-freeze-thaw effect-rainfall disaster chain. Here, we present basic information to aid the overall understanding of the preliminary characteristics of coseismic earthquake-triggered landslides, sand liquefaction, and possible follow-up disasters.

Automated summary

This study conducted three emergency field surveys using unmanned aerial vehicle (UAV) orthophoto and digital elevation model (DEM) data to investigate the coseismic surface ruptures, land liquefaction, and landslides triggered by the Maduo Earthquake. The findings include a discontinuous coseismic surface rupture zone, severe sand liquefaction regions, and the identification of tension cracks that may trigger future landslides. Further research will reveal the failure mechanism of the earthquake-triggered landslides and the disaster chain.