陕北延安地区2013年“7.3”暴雨特征及地质灾害成灾模式浅析

Characteristics and Geological Disaster Mode of the Rainstorm Happened on July 3. 2013 in Yanan Area of Shaanxi Province

2013年7月3日以来百年不遇的持续性强降雨,在陕北黄土高原延安地区引发了大量的崩塌滑坡泥石流地质灾害。通过和往年降雨情况进行对比,分析了此次强降雨的特征。调查认为,本次持续性强降雨是大范围地质灾害产生的主要诱发因素。类型主要有小规模黄土崩塌、浅表层黄土滑坡、坡面型黄土泥流,以及上述灾种复合转化形成的沟谷型泥流。阐述了这几种地质灾害的发育特征和成灾模式,从降雨、地形、地层组合、沟谷地貌等方面分析了地质灾害发生的临灾条件。

Since the persistent heavy rainfall happened on July 3, 2013, a large number of collapse and land- slide debris flow disasters are caused in Northern Shaanxi Loess Plateau. By comparing with rainfalls in the previous years, characteristics of the heavy rainfall are analyzed. According to investigation, the persistent rainstorm is the main inducing factor produced a wide range of geological disasters. There are small scale loess collapse, shallow lo- ess landslide, loess slope in mud flows and gully mudflow formed by compositing transformation in the above types of geological hazards. The development characteristics and disaster mode of the geological hazards are elaborated. The forming disaster conditions about geological hazards are analyzed from the aspect of rainfall, terrain, stratum combination, ravine landform and so on.