A catastrophic natural disaster chain of typhoon-rainstorm-landslide-barrier lake-flooding in Zhejiang Province,China

• 作者: CUI Yu-long HU Jun-hong XU Chong ZHENG Jun WEI Jiang-bo
• 来源期刊: 山地科学学报（英文版）
• 年，卷（期）: 2021,（8）
• 所属期刊栏目: Mountain Hazards
• 页码范围: 2108-2119
• 页数: 12页
• 语种: 英文

摘要

On August 10,2019,due to the effect of a rainstorm caused by Super Typhoon Lekima,a landslide occurred in Shanzao Village,China.It blocked the Shanzao stream,forming a barrier lake,and then the barrier lake burst.This is a rare natural disaster chain of typhoon-rainstorm-landslide-barrier lake-flooding.This study was built on field surveys,satellite image interpretation,the digital elevation model (DEM),engineering geological analysis and empirical regression.The purpose was to reveal the characteristics and causes of the landslide,the features and formation process of the barrier lake and the dam break flooding discharge.The results show that the volume of the landslide deposit is approximately 2.4 × 105 m3.The burst mode of the landslide dam is overtopping,which took only 22 minutes from the formation of the landslide dam to its overtopping.The dam-break peak flow was 1353 m3/s,and the average velocity was 2.8-3.0 m/s.This study shows that the strongly weathered rock and soil slope has low strength and high permeability under the condition of heavy rainfall,which reminds us the high risk of landslides and the importance of accurate early warning of landslides under heavy rainfalls in densely populated areas of Southeast China,as well as the severity of the disaster chain of typhoon-rainstorm-landslide-barrier lake-flooding.