Temporal Characteristics of Debris Flow Surges

Frontiers in Earth Science

卷:9

Xiaojun Guo¹  Yong Li²  Daochuan Liu³  Bin Yu⁴  Jun Zhang⁵  Taiqiang Yang⁵ 

[1] Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing, China;

[2] Key Laboratory of Mountain Hazards and Earth Surface Processes, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, China;

[3] Sichuan Highway Planning, Survey, Design and Research Institute Ltd., Chengdu, China;

[4] State Key Laboratory of Geohazards Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu, China;

[5] University of Chinese Academy of Sciences, Beijing, China;

关键词: stationary;    persistence;    long-term memory;    Hurst exponent;    debris flow;   

DOI  :  10.3389/feart.2021.660655

来源: DOAJ

【 摘 要 】

Debris flow is one of the most destructive geomorphological events in mountainous watersheds, which usually appears in the form of successive surge waves as observed all over the world. In particular, debris flows in the Jiangjia Gully in southwest China have displayed a great variety of surge phenomena; each debris flow event contains tens or hundreds of separate surges originating from different sources. Therefore, the surge sequence of an event must encode the information of debris flow developing. The unmanned aerial vehicle photos provide an overview of debris flow sources, showing the different potentials of the debris flow and surge sequences present various patterns responding to the rainfall events. Then the variety of rainfalls and material sources determine the diversity of surge sequence. Using time series analysis to the surge discharge sequences, we calculate the Hurst exponent, the autocorrelation function, and the power spectrum exponent and find that all the sequences commonly share the property of long-term memory and these parameters are correlated in an exponential form, with values depending on rainfall patterns. Moreover, all events show a gross trend of discharge decay, despite the local rainfall process, which implies the intrinsic nature of the surge sequence as a systematic behavior of watershed. It is expected that these findings are heuristic for establishing mechanisms of debris flow initiation and evolution in a watershed.

【 授权许可】

Unknown