中文摘要：

以典型的云南东川蒋家沟为例,根据Strahler面积-高程曲线的积分将其分区,揭示了流域的演化差异,证明了泥石流发生在特定的演化区域,并具有特定的物质组成。通过概率模型,定性说明了泥石流在流域的形成和扩张,其结果就表现为间歇性的阵流。阵流的时空特征反过来证明了泥石流的系统性。统计还表明,阵流的流量分布和衰减取决于最大流量;最大流量序列很好继承了作为流域系统行为的动力学特征。最后,可以根据单沟泥石流的过程系统考察区域泥石流活动。泥石流在大尺度水系的分布,从概率过程看,完全等同于泥石流源地小分支在单个流域的分布,而且满足相似的分布特征。

英文摘要：

Based on the Strahler Hypsometric （Area-Altitude） curve, the Jiagjiagou Gulley of Yunnan is divided into four types of sub-regions, showing that debris flows are likely to develop in the subregions that stay in the spe- cial evolutionary episode featured by the hypsometric integral between O. 55 and 0.65. Also favoring debris flow in this subregion is the soil that assumes scaling property in grain size distribution. A simplified hierarchical model is introduced to illustrate the formation and extension of debris flow under the control of the self-similarity of the valley structure and the distribution of tributary flows. Then debris flow reduces to the behavior of a hierarchy system; and the surges separated in time can be interpreted as the result of the systemic evolution. In particular, the exponential distribution of the surge discharge provides a sign of the system dynamics in the same way the power-law frequency- magnitude relation signs the SOC feature. It is also notable that the exponent is related to the peak discharge by a power-law relationship. Therefore the peak discharge plays a significant role in governing the systematic behavior of debris flow. These findings provide a new framework for addressing problems in the field of debris flow study. Fi- nally, the scenario for the debris flow of Jiangjiagou Gully can be extended to the large scale. The debris flows in a large river system satisfy the same distribution similar to the distribution of tributaries in a single valley. This pro- vides a probability picture for the debris flow activities in regional scale.