Deformation Analysis of Jishishan Mw6.2 Earthquake on the Landslide Hazard Areas

Objectives: Earthquake events can easily induce or accelerate the landslide failure. On 18th December 2023, an Mw 6.2 earthquake occurred in Jishishan County, Linxia, Gansu Province, with a focal depth of only 10 km. The surrounding landslide disaster-prone areas are faced with great hidden danger of sudden or advanced failure, and it is urgent to conduct rapid analysis and assessment of deformation in prone areas. Methods: In this paper, the global navigation satellite system（GNSS） and accelerometer real-time observation data of four landslide prone areas at different distances (64 km, 111 km, 140 km and 240 km) from the seismic center, and the damage effects of the main shock and aftershock on the landslide were comprehensively analyzed with precise point positioning（PPP）, real time kinematic, GNSS & accelerometer adaptive coupled technology and wavelet transform. Results: The results show that the elastic displacement of 1 cm and the permanent displacement of 0.5 cm are detected in the Heifangtai landslide, 64 km away from the seismic center, while the obvious impact response are detected in the Zhouqu landslide, 240 km away from the seismic center. The vibration frequency was between 0 -10 Hz, and the peak acceleration reached 0.035 m/s², which increased the risk of landslide failure. Conclusions: The displacement and vibration effects of the earthquake on the landslide are mainly concentrated in the horizontal direction, and the vertical direction is not significant. It is suggested the landslide disaster-prone areas within 64 km of Jishishan County should be investigated and evaluated as soon as possible to prevent secondary disaster damage.