Glacier detachment chain process in the Amney Machen Mountain
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摘要:冰川滑塌是近年来涌现的一种新形式冰川灾害.21世纪以来,青藏高原地区发生10多起冰川滑塌事件,其中高原东北部阿尼玛卿山晓玛沟冰川分别在2004、2007、2016和2019年连续发生4次.利用多序列遥感影像和现有资料的整合统计对近35年来晓玛沟冰川形态、流速特征等进行分析,厘清了4次冰川滑塌事件发生的诱因以及潜在的隐患点.结果表明,4次冰川滑塌发生前期的冰川跃动或末端前进、冰川后缘冰-岩崩、异常高温降水、易于滑动产生的基岩性质等与冰川滑塌事件的发生密切相关.观察到冰川后缘陡坡区在2000—2011年间发生4次规模较大的冰-岩崩,为多次冰川滑塌的发生提供了物质和动力基础.未来几年内再次发生冰川滑塌的可能性极大.2019年冰川滑塌发生后,晓玛沟冰川再次向前滑动;近年来,冰川后缘新发育的不稳定斜坡冰裂隙发育明显增多;斜坡冰流速的变化与下部冰川稳定性之间存在内在联系,在冰川滑塌发生的相关年份斜坡冰流速明显较快.根据对阿尼玛卿山4次冰川滑塌诱因的分析以及新隐患点的判定,提出结合遥感影像和临近气象站点资料的便易手段,加强对晓玛沟内冰川形态和运动特征等的监测,以及时关注和预测未来灾害的发生.Abstract:Glacial detachment is a new type of glacial hazard that has emerged recently.Since 2000, more than a dozen glacier detachments happened in the Tibetan Plateau.The Xiaomagou glacier of Amney Machen Mountain collapsed multiple times, in 2004, 2007, 2016 and 2019.Multi-sequence remote sensing images were used to analyze Xiaomagou glacier morphology and flow characteristics over the past 35 years.This combined with meteorological data and prior literatures revealed triggers for glacier collapse, glacier hazard potential in the future were identified.Previous glacier surges or slides, ice-rock avalanches at back slope, high temperature and/or precipitation, and glacier bed nature are all closely related to the occurrence of glacier collapse.Four large-scale ice-rock avalanches were observed in the glacier back slope zones from 2000-2011, which provided a material and dynamic basis for glacier collapses.The possibility of another glacier collapse in the next few years is extremely high.After the 2019 glacier detachment, Xiaomagou glacier has squirmed forward again.Newly developed unstable slope at the back edge of the glacier has been found. Increased ice crevasses were identified.Changes in slope ice velocity are likely related to relevant collapses.Understanding of triggers of Amney Machen glacier collapses, determination of potential hazard slope, together suggest that glacier morphology and movement characteristics should be monitored, remote sensing should be combined with meteorological data, to predict future disasters in a timely manner.
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表 1晓玛沟和青龙沟发生的冰川滑塌和堰塞湖溃决灾害事件统计
序号 事件 时间 区域 脱离区
面积/km2脱离区
平均坡度/(°)脱离体积/
106m3描述 诱因 来源 1 冰川滑塌 2004-01-26
—02-10积累区 0.207 22 21.5 碎屑物在沉积区堆积平均厚度约10 m,破坏了下游大量的草场.形成堰塞湖 冰川跃动,冰-岩崩,降水,基岩性质 本研究,[46] 2 冰川滑塌 2007-10-08 积累区 0.139 16 6.54 碎屑物在沉积区堆积平均厚度约6 m.对下游的道路、涵洞造成破坏.形成堰塞湖 冰川跃动,冰-岩崩,高温降水,基岩性质 本研究,[46] 3 冰川滑塌 2016-10-06 积累区 0.085 23 4.25 碎屑物在沉积区堆积平均厚度约5 m.形成堰塞湖 冰川跃动,冰-岩崩,高温(可能),基岩性质 本研究,[46] 4 冰川滑塌 2019-07-09
—07-14积累区 0.028 13 1.12 量级小,形成的碎屑流未对下方道路造成破坏 冰川跃动,冰-岩崩,降水(可能),基岩性质 本研究,[14] 5 堰塞湖
溃决2005-07-04 青龙沟 0.631 5.38 青龙沟主河道发育得最大的堰塞湖溃决,发生过程缓慢,7月5日溃决洪峰达到最大 坝体中的冰融化,水压力增大 本研究,[46] 表 2选取的可用遥感影像和数字高程模型
序号 影像名称 采集时间 精度/m 应用 1 KH-4A 1964-12-30 2.7 冰川边界提取 2 Orbview-3 2005-06-21 1.0 冰崩信息提取 3 Landsat4/5 TM 1986-10-31、1987-08-15、1988-02-07、1989-09-21、1990-06-20、1990-07-06、1991-09-11、1992-06-09、1993-08-31、1994-05-14、1994-11-06、1995-07-20、1997-08-10、1998-07-12、1999-07-31、2000-04-28、2001-07-04、2004-09-14、2006-09-20、2007-05-02、2007-09-23、2008-03-17、2009-08-11、2010-08-14、 30.0 冰川边界提取 4 Landsat7 ETM+ 2002-08-16、2003-05-31、2004-01-26、2011-07-08 30.0 冰川边界提取 5 Landsat8 OLI 2013-04-16、2014-07-24、2015-08-12 30.0 冰川边界提取 6 ASTER 2000-10-04、2001-09-30、2002-12-13、2004-03-05、2004-09-13、2005-09-16、2006-03-27、2008-07-15、2012-09-12 15.0 冰川边界提取;冰崩信息提取 7 Sentinel-2A/B 2016-07-30、2016-09-28、2017-08-04、2018-09-28、2019-04-26、2019-07-30、2019-08-29、2020-09-17、2021-09-07 10.0 冰川流速、边界提取 8 HMA DEM 2015 8.0 冰崩信息提取 9 PALSAR 2007-08-15 12.5 冰崩信息提取 10 NASA 2000 30.0 冰崩信息提取 表 3晓玛沟发生的量级较高的冰-岩崩事件统计
序号 时间 区域 脱离区
面积/km2脱离区
平均坡度/(°)脱离体积/
106m3描述 诱因 来源 1 2000-04—
2001-07陡坡区1 0.107 29 2.24~6.34 在旧的不稳定的冰川后缘陡坡区1上,冰体裹挟下方岩体向下滑塌,最终碎屑物堆积在冰舌上端 地震,气候变化导致的斜坡稳定性降低 本研究,[49] 2 2003-05—
2004-01陡坡区2 0.023 36 0.82~1.85 在新的不稳定的冰川后缘陡坡区2上,冰体同下方基岩碎屑发生滑塌,最终堆积在冰舌上端 气候变化导致的斜坡稳定性降低 本研究,[49] 3 2007-09-15—
11-02陡坡区2 0.022 34 0.42~1.22 脱离区2下部进一步发生滑塌,此次事件可能是由多次小冰崩组合而成 气候变化导致的斜坡稳定性降低 本研究 4 2010-08—
2011-06陡坡区2 0.108 42 6.84~11.23 脱离区2上部进一步发生滑塌,碎屑物没有冲出沟谷,而是堆积在冰舌上端 气候变化导致的斜坡稳定性降低 本研究 -
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