2010年“8.8”舟曲特大山洪泥石流灾害形成的气候特征及地质地理环境分析

利用舟曲气象和地质资料,分析了2010年8月8日发生的"8.8"舟曲特大山洪泥石流灾害形成的气候特征和地质地理环境.这次泥石流是在舟曲特殊的地质地貌和地理环境下,由于前期干旱,突遇强降水而发生的一次特大地质灾害.崩塌、滑坡、地震和人为因素,特别是"5.12"汶川地震,较大程度上破坏了舟曲地质,为泥石流提供了丰富的物质来源;前期干旱在一定程度上加剧了这次灾害;超历史极值的强降水是触发泥石流的直接因素.通过对舟曲气候研究表明,7、8月降雨频繁,而且过程雨量大,尤其8月上旬大雨发生频率最高,应密切关注可能引发的地质灾害.加强对地质地貌的保护,研究历史气候及月季气候特征对泥石流发生的影响,确定在不同地形和地质地貌背景下的泥石流降水量阈值,对泥石流灾害发生的预报有着十分重要的意义.

Climatic and Geological Environmental Characteristics of the Exceptional Debris Flow Outburst in Zhouqu,Gansu Province,on 8 August,2010

In this paper,by using of meteorological and geological data of Zhouqu,the climate and geology characteristics of exceptional debris flow outburst in Zhouqu on 8 August,2010 is analyzed.On the background of Zhouqu special geological features and geographical environment,the pre-drought and the sudden heavy rainfall resulted in the large geological disaster.Collapse,landslide,earthquake and human activity,especially the Wenchuan earthquake on 12 May,2008,have destroyed the Zhouqu geologic environment in a great extent and provided a lot of material for debris flow.In certain extent,the pre-drought would aggravate the disaster;and extreme precipitation,which has not been seen in the history record,is the direct factor of trigger the debris flow.By analyzing the Zhouqu climate data,it is found that rainfall intensity in July and August,particularly in the early August,has the highest frequency,to which should pay special attention.It is of great significance to strengthen the protection of geological environment,to research climate impact on debris flow and to determine the precipitation threshold,which is important for forecasting debris flow.