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基于对汶川8.0级地震同震地质灾害和震后5年来龙门山中北段地质灾害空间分布的刻画,对震后泥石流灾害空间分布及其控制因素进行分析,获得以下认识:震后泥石流集中分布在北川-映秀断裂上盘10 km范围以内,相对于同震崩塌、滑坡具有更明显的上盘效应。震后泥石流的空间分布主要受松散堆积物分布范围、地形地貌、岩性、降水等多种因素控制。其中同震崩塌、滑坡松散堆积物为震后泥石流的发生提供了重要的物质来源;地形地貌是控制震后泥石流发生的重要影响因素,为泥石流提供了势能和启动的空间条件;震后泥石流集中发生在前震旦系彭灌杂岩和古生界粉砂岩、砂岩等岩性分布区;降水是导致震后泥石流地质灾害发生的直接诱发因素。
Based on the description of the coseismic geocentric disaster of the Wenchuan Ms 8.0 earthquake and the spatial distribution of geological disasters in the middle and northern parts of the Longmenshan area since the Wenchuan M 8.0 earthquake, the spatial distribution of the debris flow disaster and its controlling factors after the earthquake are analyzed. The following conclusions are obtained: Within 10 km of the upper reaches of the Beichuan - Yingxiu fault, the landslide has a more obvious upper plate effect relative to the coseismic collapse. After the earthquake, the spatial distribution of debris flow was mainly controlled by various factors such as the distribution of loose sediments, topography, lithology and precipitation. Among them, the crashes and unconsolidated landslides provide an important material source for the occurrence of debris flow after the earthquake. The topography is an important factor for controlling the occurrence of debris flow and provides the potential conditions for the debris flow and the starting conditions. After the earthquake, the debris flow concentrates Occurred in the Pre-Sinian Peng influx and Paleozoic siltstone, sandstone and other lithology distribution; precipitation is the direct cause of post-earthquake debris flow geological disasters occur.