[1]LI Yuanling,WANG Junchao,CHEN Long,et al.Characteristics and Geneses of the Group-Occurring Debris Flows Along Parlung Zangbo River Zone in 2016[J].Research of Soil and Water Conservation,2018,25(06):397-402.
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Research of Soil and Water Conservation[ISSN 1005-3409/CN 61-1272/P] Volume:
25
Number of periods:
2018 06
Page number:
397-402
Column:
Public date:
2018-10-26
- Title:
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Characteristics and Geneses of the Group-Occurring Debris Flows Along Parlung Zangbo River Zone in 2016
- Author(s):
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LI Yuanling1,2, WANG Junchao1,2, CHEN Long1,2, LIU Jiankang1,2, YANG Dongxu1,2, ZHANG Jiajia1,2
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1. Institute of Exploration Technology, China Academy of Geological Sciences, Chengdu 611734, China;
2. Technical Center for Geological Hazard Prevention and Control, China Geological Survey, Chengdu 611734, China
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- Keywords:
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group-occurring debris flows; Parlung Zangbo River Zone; south-eastern Tibet; critical rainfall; block-outburst
- CLC:
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P642.23
- DOI:
-
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- Abstract:
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Parlung Zangbo River Basin has the features of high mountains, intensive tectonism and widespread glacier. The glacial debris flows along Parlung Zangbo River Basin was large in number and scale with dense dissemination and high frequency. The group-occurring debris flow caused heavy losses of property and blocked the G318 Road on September 5th, 2016. In order to investigate the cause of the debris flow and strengthen disaster monitoring, geography, sources of debris flows and hydrodynamic conditions were analyzed. The results indicated that the debris flows were easily formed because of the favorable landform, giant gaps among different elevation, great longitudinal river slopes and deeply ice eroded valley. The unconsolidated glacial sediments are the main sources of debris flow in this area. In addition, as with a less wide gully and a more abundant provenance of collapse and landslide, the debris flow block-outburst occurred frequently on north bank while the debris flow gully on the south bank occurred less with a contrary condition of the inducement. The predominant triggering factor of this group-occurring glacial debris flow was the heavy rainfall. The antecedent rainfall had saturated the provenance which was then initiated by the following heavy rain. The Bitong Valley debris flow occurred at 2:00 am through research. However, it reached the Parlung Zangbo River Basin a few hours later because of being blocked. The debris flow in Chidanlongba Valley started at 11:00 am and then rushed out the gully and deposited on the old alluvial fans. The hourly rainfall which triggered the debris flow measured in the piedmont was 3.3~3.6 mm, the estimated hourly rainfall was 7.6~8.3 mm in the debris flow initiated area.