西藏林芝6.9级地震崩塌地质灾害模式浅析

Simple Analysis on the Collapse Geohazard Failure Modes Induced by Linzhi M_s 6.9 Earthquake,Tibet

2017年11月18日,西藏林芝米林县发生M_s6.9级地震,震源深度10 km。为了揭示林芝6.9级地震触发的地质灾害特征,通过现场野外实地调查和卫星遥感解译得出:林芝6.9级地震触发的地震地质灾害以小型崩塌为主,分为土质崩塌和岩质崩塌,土质崩塌模式主要有浅表层崩塌,堆积体中的块石、孤石等震动滚落崩塌;岩质崩塌模式有:拉裂-倾倒崩塌、震动-滑移崩塌、震动-坠落式崩塌;林芝地震触发的地质灾害主要受地形地貌,地层岩性组合,人类工程建设活动影响;具有明显的地形放大效应,崩塌源主要分布在山体斜坡的凸出部位和坡性转折部位以及单薄山脊等强卸荷部位。

At 18th November 2017,a M s6.9 earthquake,with a focal depth of 10 km,struck Linzhi prefecture,Tibet,China.In order to reveal the typical characteristics of geohazards triggered by Linzhi earthquake,an emergency investigation and remote sensing interpretation are carried out.The results show that the geohazards that triggered by Linzhi earthquake are mainly small-scale rockfalls and residual accumulation failure.The accumulation failure also can be divided into shallow collapses and single boulder,in accumulation,failure.The failure modes of rockfall mainly consist crack-toppling failure,Shaking-sliding failure and Shaking-failing failure.Topography and geomorphology,lithology and human activity have obvious influence on distribution and occurrence of geohazards.There exists back slope effect in geohazard distribution.The collapse is mainly distributed in the up part of mountain,ridge and slope break,it shows topographic amplification effect.