摘要
The edge of the Qinghai-Tibet Plateau is characterized by high topographic relief, significant tectonic motion, extreme precipitation, and densely populated active debris flow gullies. It is essential to scientifically categorize the debris flow gullies to understand their mechanisms, prevent and mitigate debris flow disasters, and find out strategies to restore the ecology. The present study carried out topographical measurements and statistical analyses of seven regions on the edge of the Qinghai-Tibet Plateau, in which active debris flow gullies are concentrated. The debris flow gullies are classified into three types by means of nonmetric multidimensional scaling. Type I is formed by rainstorms in exposed bedrock areas, Type II is formed by glaciers in exposed bedrock areas, and Type III is formed by rainstorms in depositional basins. The variation in landforms of the three types is analyzed using Kruskal-Wallis tests. The sources of loose material and the characteristics of water flow and sediment transport in all the three types of debris flow gullies are discussed from the aspects of geology, topography, and climate. It is shown that the activity of Type II increases along with the warming of the Qinghai-Tibet Plateau, and the activities of types I and III increase along with the frequency of extreme rainfalls.
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