| 摘要: |
| 青藏高原东缘是全球重要的活动构造区，高原峡谷区斜坡陡峻，高位崩滑灾害多发。采用遥感解译、地面调查、钻孔勘探及测年分析等方法，研究了西藏洛隆察达沟和易贡扎木弄沟两处高位崩滑堆积体的多动力多期次演化特征。研究结果表明：(1)沿陡峻沟道发生的高位崩滑灾害多为复合成因，兼具内动力和外动力作用交替促发特征；(2)洛隆察达沟晚更新世以来的堆积物形成序列可分为4期，分别经历了以冰川作用为主的冰碛物堆积、古地震引发的高位崩滑-碎屑流堆积、气候变暖背景下的冰-岩崩滑堆积及近代重力崩滑堆积；(3)易贡扎木弄沟在过去5500年中，先后发生了8次以上较大规模崩滑堆积，测年结果显示了巨型崩滑事件存在百年数量级的复发周期，由于不同期次巨型崩滑体的成因不同，复发周期可能存在长、中、短的差异；(4)近年来受全球气候变化影响，冰-岩崩滑灾害频现，可能成为高原峡谷区高位远程地质灾害研究的焦点。本文关于高位崩滑灾害多期次演化过程的认识对于高原峡谷区重大地质灾害防灾减灾具有一定启示意义。 |
| 关键词: 高位地质灾害 古地震 冰川作用 复发周期 冰-岩崩滑 |
| DOI：10.19826/j.cnki.1009-3850.2022.04008 |
| 附件 |
| 投稿时间：2021-11-07修订日期：2021-12-30 |
| 基金项目:国家自然科学基金重大项目(41941017)、国家自然科学基金重点项目(41731287)、国家地质调查项目(DD20190505)联合资助 |
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| Multi-dynamic and multi-phase evolution of high-position avalanche hazards on the eastern margin of the Qinghai-Tibet Plateau |
| ZHANG Yongshuang, REN Sanshao, GUO Changbao, WU Ruian, DU Guoliang, LI Jinqiu |
(1. Institute of hydrogeology and environmental geology, CAGS, Shijiazhuang 050061, China;
2. Institute of Geomechanics, CAGS, Beijing 100081, China;
3. Hebei University of Geosciences, Shijiazhuang 050031, China) |
| Abstract: |
| The eastern margin of the Qinghai-Tibet Plateau is an important active tectonic zone in the world, with steep slopes and frequent high-position avalanche hazards in the plateau canyon area. Combined with remote sensing interpretation, field investigation, borehole exploration and dating analysis, the multi-phase evolution characteristics of two high-position avalanches are studied in Luolong county and Yigong county, Tibet, China. The research results show that: (1) Most of the high-position avalanche hazards occurring along steep gullies are caused by complex factors, with the characteristics of alternating internal and external dynamic action; (2) The formation sequence of the deposits since the Late Pleistocene in the Chada gully, Luolong county, can be divided into four phases, which have respectively experienced the accumulation of moraines dominated by glaciation, the accumulation of high-position avalanche-debris flow triggered by paleo-earthquake, and the accumulation of ice-rock avalanche in the context of climate warming and the accumulation of recent gravity avalanche; (3) In the past 5,500 years, the Zhamu gulley in Yigong county has experienced more than 8 times large-scale avalanches. The dating results show that the giant avalanche event has a recurrence cycle on the order of hundreds years. Due to the different causes of giant avalanches in different stages, the recurrence cycle may be long, medium, or short; (4) In recent years, affected by global climate change, ice-rock avalanche hazards have occurred frequently, which may become the focus of research on high-position and long run-out geological hazards in plateau and canyon areas. The understanding of the multi-phase evolution process of high-position avalanche hazards in this paper has certain enlightenments for the prevention and mitigation of major geological hazards in the plateau canyon areas. |
| Key words: high-position geohazard paleo-earthquake glaciation recurrence period ice-rock avalanche |
