Risk assessment of single gully debris flows based on dynamic changes of provenance in the Wenchuan earthquake zone: A case study of Qipan gully

• Published in: Zhongguo dizhi zaihai yu fangzhi xuebao Vol. 36; no. 1; pp. 16 - 27
• Main Authors: Na SU, Linrong XU, Yongwei LI, Jiashen LI, Yulan TANG
• Format: Journal Article
• Language: Chinese
• Published: Editorial Office of The Chinese Journal of Geological Hazard and Control 01.02.2025
• Subjects: cloud model; combined weighting method; debris flow; provenance changes; risk assessment; wenchuan earthquake
• ISSN: 1003-8035
• DOI: 10.16031/j.cnki.issn.1003-8035.202308010

Following the catastrophic “5•12” Wenchuan earthquake, extensive debris was deposited on mountain surfaces in the earthquake zone, and significant vegetation damage occurred, providing abundant material for debris flow outbreaks and substantially increasing their risk. Previous studies primarily focused on vegetation recovery when assessing post-earthquake debris flow risks. However, field surveys revealed that large quantities of dynamic storage materials in the gullies significantly impact risk assessments. Based on field survey data, this study uses Qipan gully in Wenchuan County as a research subject and employs multi-source and multi-scale monitoring tools (Landsat series, Quick-bird, and UAVs) to analyze and statistically assess the source materials on slopes and gullies both pre- and post-earthquake. A dynamic risk assessment model for debris flow is constructed using game theory combined with a cloud model, assessing the risk from 2005 to 2019. Findings indicate that post-earthquake slope material sou