芦山地震触发崩塌滑坡的优势方向与机理

利用芦山地震强震记录、水系图和1 754个地震触发崩塌滑坡数据,对芦山地震触发崩塌滑坡的优势方向的控制因素进行了研究.对比分析了崩塌滑坡数的优势方向与研究区自然坡体的优势坡向;基于对抗性原理,确定了芦山震区新构造应力场方向;对崩塌滑坡确定性系数分区进行了分析.认为自然坡体的优势方向是决定崩塌滑坡方向的首要因素,但应考虑不对称地形造成的坡向分异现象;新构造应力场是崩塌滑坡方向的全局性影响因素,地震台站的最大累计加速度方向是其代表区域内崩塌滑坡方向的影响因素.对于盲断层型地震,上述三因素对地震触发崩塌滑坡方向的控制效应可能是具有普适性意义的规律. 

Predominant Direction and Mechanism of Landslides Triggered by Lushan Earthquake

Based on Lushan earthquake records, drainage systems and 1 754 earthquake-induced landslides, control factors of the directions of landslides triggered by earthquake were researched. The dominant direction of landslide number and the dominant aspect of natural slopes were compared; the direction of new tectonic stress field in the Lushan seismic area was determined from the antagonism principle; the certainty factor for landslide in each sub-area was determined by GIS spatial analyses. The research shows that the predominant direction of natural slopes is a control factor of the directions of landslides triggered by an earthquake, but the asymmetry of mountain slope landform should be considered; the direction of new tectonic stress field is a global factor of the directions of landslides; the direction of the maximum cumulative acceleration at a seismic station also control the sensitivity directions of landslides in the station area; to an earthquake resulted from a blind fault, it may be a universal law that the above three factors control the direction of earthquake-triggered landslides.