Impact Analysis of the 6.2 Magnitude Earthquake on Landslide Deformation and near-Earth space Environment in Jishishan, Gansu Province

Objectives:The 6.2 magnitude earthquake that struck Jishishan on 18 December 2023 is highly prone to causing landslides and other disasters. In order to reduce the damage caused by the earthquake and its secondary disasters to people's lives and properties, it is necessary to monitor the landslide area and its near-earth spatial environment as soon as possible. Methods: The raw global navigation satellite system observation data of the landslide, the dam and the reference station, which are about 51 km away from the epicentre of the earthquake, are collected for precise point positioning (PPP) solving, and the site displacements are counted, The effects of the earthquake on the landslide and the near-Earth spatial environment were studied and analysed by counting the changes in zenith tropospheric delay (ZTD) and precipitable water vapor (PWV). Results:The experimental results show that the earthquake did not cause transient damage to the landslide, but the earthquake will damage the stability of the landslide, in the day after the earthquake part of the landslide site slow displacement of up to 10 mm or more; In addition, the zenith tropospheric delay after the earthquake showed anomalous increase in the trend of change, which is mainly due to the water vapour anomalous changes. Conclusions:The vicinity of this landslide, stations HP03 and HP04, requires timely and focused surveys to assess the potential for hazard. Long-term monitoring of other landslide sites is also required to keep abreast of the risk of landslide hazards. Since this earthquake occurred in winter, the climate is dry and the PWV value is small, there is a lack of rainfall conditions, so although the ZTD and PWV changed abnormally, it will not lead to abnormal rainfall in the earthquake area, which is conducive to the rescue work after the earthquake.