1.The happening of debris flow is a complicated problem, and it is the outcome of polysynthesism coaction, this brought difficulty to analytical prediction of development trend of debris flow.

1.摘要泥石流的发生与否是其复杂的问题，而且是由种因素共同作用的结果，泥石流活动发展趋势的分析预测带来了困难。