汶川MS 8.0级地震诱发崩滑特点及其与地震动参数对应关系初析

2008年5月12日汶川MS8.0级强震诱发了大规模的崩塌滑坡地质灾害,不仅造成了巨额的经济损失,而且造成了众多的人员伤亡。汶川地震诱发崩滑分布受发震断层影响明显,而且在断层两侧不对称分布。分析表明汶川地震诱发崩滑与地震烈度存在相关性,但没有明确的对应关系,与震级、地震动峰值加速度关系较为密切。利用汶川地震在龙门山断裂带及附近地区获得的近40个台站的强震记录,对地震诱发崩滑与地震动峰值加速度的关系进行了初步研究,得到如下结果:地震诱发崩滑与地震动峰值加速度存在正相关性;水平向地震动水平对斜坡稳定性影响更大;在龙门山断裂带及其附近地区存在0.2g的地震动峰值加速度分界线,大于此值时崩滑明显增多。研究结果表明利用地震动峰值加速度对地震诱发崩滑进行研究具有一定理论和实际意义。

Characteristics of landslides induced by Wenchuan MS 8.0 Earthquake and preliminary analysis of their relations with ground motion parameters

The MS 8.0 Wenchuan Earthquake,which occurred on May 12th,2008,induced large scale landslides which distributed across wide areas and caused great losses in both economy and casualty.Landslides triggered by Wenchuan Earthquake are obviously affected by the fault and distributed asymmetrically on the two sides of the fault.Analysis shows that the landslides triggered by Wenchuan Earthquake have some relation but not a definite relation with the earthquake intensity.However,there does exist an obvious relation between these landslides and earthquake magnitude or peak ground acceleration (PGA).A basic analysis on the relation between earthquake-induced landslides and PGA parameter is given on the basis of the near 40 groups of records distributed along the Longmenshan faults.The conclusion is:there exists a normal relation between earthquake induced-landslides and PGA;the stability of the slopes is affected more by the horizontal records of the ground motion;and there is a 0.2g boundary among the PGA records with which greater PGA causes more landslides around the Longmenshan faults and its neighbourhood.The results demonstrate that it is useful in both theory and practice to study earthquake-induced landslides with PGA.