云南蒋家沟泥石流运动特征及其发展趋势

根据蒋家沟1965~2005年的泥石流运动观测资料与会泽气象站1965~2005年日降水资料,应用Hurst指数分析泥石流的运动要素,研究发现:泥石流年输沙量的Hurst指数为0.682时,年输沙量呈较强的正持续性,未来呈增长趋势;降雨量的Hurst指数0.605时,降雨量呈较弱的正持续性,未来呈较弱的增长趋势。同时,运用小波分析方法,发现泥石流输沙量具有多时间尺度周期的特征,主要表现为:第8、14和24年分别为其第1、2和3活动周期;结合小波方差图分析可知:在未来15 a以上,年输沙量将呈减少趋势,泥石流活跃程度弱;而15 a以内,未来将会保持较短时间的增加趋势,泥石流活跃程度强。综合以上分析可知:蒋家沟泥石流具有规模巨大,作用强烈,类型齐全等主要特征。

CHARACTERISTICS AND EVOLUTION OF DEBRIS FLOW MOTION IN JIANGJIA GULLY IN YUNNAN PROVINCE

Based on the 1965-2005 observation data of Jiangjia Gully and the 1965-2005 daily precipitation data of Huize County in Yunnan Province, several movement elements of debris flow were detailed analyzed such as discharge, bulk density, sediment discharge and its development. Based on the Hurst index method, the Hurst index of debris flow sediment discharge was calculated to be 0.682, showing a strong positive sustainability and strong growth in future. The rainfall Hurst index was 0.605, showing a weaker growth trend in the future. At the same time, with the wavelet analysis method, annual sediment discharge was found to had several time dimensions of periods: 8 years, 14 years, and 24 years was the first three main cycles. Annual sediment discharge would decrease and the debris flow activity would be weaker in the coming 15 years. Within 15 years, the debris flow activity would have a shorter increase and the debris flow activity would be strong. Huge scale, strong hazard and different types of Jiangjia Gully debris flows were concluded in the research.