摘要:
喜马拉雅山地区的冰川湖(简称“冰湖”)受形成条件和自然环境的影响,往往会发生溃决,造成洪水和泥石流灾害,严重威胁人类生产和生活、生存与发展,成为该地区一重大地质灾害隐患。采用QuickBird和ETM等卫星遥感数据,结合野外考察,研究喜马拉雅山地区冰湖溃决灾害隐患后认为:①喜马拉雅山地区的冰湖在区域分布上具有由东南向西北逐步递减的趋势,冰湖分布最多的是山南、日喀则、林芝和阿里地区,分布密度最大的是山南地区的洛扎一带;②喜马拉雅山地区存在19个溃决灾害隐患的冰湖,均为冰川终碛湖,其中13个湖存在重大溃决灾害隐患,6个存在较大溃决灾害隐患;③引起冰川终碛湖溃决的激发因素较多,其中冰湖周围的冰崩、雪崩、基岩崩塌和滑坡入湖涌浪溃坝是最重要的原因。研究结果对西藏地区冰湖溃决灾害的预警与防治具有重要意义。
关键词:
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冰川终碛湖
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溃决
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隐患
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遥感
Abstract:
Under the impact of formation conditions and natural environment , moraine -dammed lake outbursts take place frequently and then give rise to floods and mudslides , which menaces people's production , life, survival and development and becomes one of the great geohazard hidden dangers in the Himalayas .Using QuickBird and ETM data of remote sensing satellite and combining the investigations in field work , the authors studied the glacier lake outburst potential .The research results show that the areal distribution of glacier lakes presents a trend of decrease gradually from SE to NW in the Himalayas .Most of the glacier lakes are distributed in Shannan , Shigatse , Nyingchi and Ngari .The region of maximal distribution density is Lho -brag area of Shannan .It can be found that there are nineteen glacier lakes , all of which are moraine -dammed lakes that have outburst hazard potential . Among the nineteen glacier lakes , there are 13 glacier lakes having great outburst hazard potential and 6 glacier lakes having secondary great outburst hazard potential .It is also indicated that there are several trigger factors impacting instability of moraine -dammed lakes, whose foremost reasons are surge triggered by avalanche , bedrock collapse , and rock avalanche around the moraine -dammed lakes .
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