Characteristics and temporal-spatial distribution of geohazards in western Sichuan

Affected by the uplifting of the Qinghai-Tibet Plateau and the deep cutting of rivers in the Qinghai-Tibet Plateau, a total of 16,411 geohazards, mainly landslides and debris flows, have developed in the western Sichuan, which is an area with high risk of geohazards in China. By means of data collection, mathematical statistics and ArcGIS software analysis, we find that the geohazards are characterized by complex formation mechanism, sudden-group-chain occurrence, and great harm in Western Sichuan. The formation modes of geological disasters are different. The main deformation modes of landslides are slip-crack-shear, retaining wall-break, along the bedding creep-shear, toppling fracture of antidumping rock, etc. The formation mechanism of debris flow are mainly soil - hydraulic drive type and blocking collapse type. Collapse instability mainly includes sliding, toppling and falling. The spatial distribution are mainly controlled by landform and active faults, which are of the distribution of a zone in the low and middle mountains, and a certain band along the active fault zone and deep river valley. Affected by earthquakes and heavy rainfall, geological disasters vary greatly from year to year. Geological disasters occurred frequently and frequently in 2008, 2009, 2013 and 2017.