甘肃积石山6.2级地震对滑坡形变及近地空间环境影响分析

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

  • 摘要: 2023 年 12 月 18 日积石山发生 6.2 级地震,为减少地震及其次生灾害对人民生命财产造成的损失,研究震后滑坡及近地空间环境变化对地震次生灾害的防治具有重要意义。采集距离震源中心 51 km 左右的滑坡、大坝以及基准站的全球导航卫星系统原始观测数据进行精密单点定位解算,通过统计站点位移、天顶对流层延迟(zenith tropospheric delay,ZTD)和大气可降水量的变化情况,研究分析了地震对滑坡作用及近地空间环境的影响。实验结果表明,本次地震并未对该处滑坡造成瞬时破坏,但地震会破坏滑坡稳定性,在地震后一天部分滑坡点位缓慢位移高达 10 mm 以上;此外,在地震后天顶对流层延迟呈现出异常增高的变化趋势;对影响其异常变化的原因进行分析,发现气压变化对震后 ZTD 变化有一定影响,但其主要是由于水汽异常变化所导致,证明了地震会导致震区水汽异常增大。本文研究将为后续地震所引发滑坡变形和空间环境变化等相关研究做参考。

     

    Abstract: 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.

     

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