2022年9月5日，位于四川省西部、康藏高原东南部的四川泸定县发生了6.8级地震，地震造成93人遇难，25人失联，大量房屋被毁。海螺沟位于此次地震震中，海螺沟冰川是亚洲的低海拔冰川之一，也是离大城市最近的一条现代冰川。海螺沟冰川是否受到此次地震的影响而出现不稳定呢？中国科学院成都山地灾害与环境研究所刘巧研究员的团队采用可见光与雷达卫星遥感数据、无人机遥感、地面相机监控等多源观测数据，对海螺沟冰川的稳定性进行了综合评估。他们撰写的“Stability of the Hailuogou glacier during the “9.5” Luding Earthquake: a preliminary assessment based on multi-source observations”一文被遴选为Journal of Mountain Science 2022年11期封面文章

Citation: Liu Q, Zhang B, Zhao B, et al. (2022) Stability of the Hailuogou glacier during the “9.5” Luding Earthquake: a preliminary assessment based on multi-source observations. Journal of Mountain Science 19(11). https://doi.org/10.1007/s11629-022-7730-x

Downloads: https://doi.org/10.1007/s11629-022-7730-x

Highlights:

（1）Multi-source satellite observations combined with ground monitoring allow a timely assessment of glacier-related hazard risks；

（2）The Hailuogou Glacier is much more stable than expected even experienced a strong seismic shake；

（3）Post-earthquake hazard risks are still high as recent strong paraglacial destabilization offer large amount of debris sources in deglaciated valleys.

Cover Story

Mountain glacier collapse or ice avalanche, usually with high mobility speed and long-run distance, could cause catastrophic disasters since they potentially initiate chain hazardous processes combined by landslides, debris flows and outburst floods in the glacierised mountains. Observed increasing frequency of widespread glacier destabilization is likely be related to atmospheric warming induced cryospheric condition changes (e.g., glaciers shrinkage and permafrost thaw), as well as the disturbance by their adjacent seismic activities.

Mt. Gongga (7556 m a.s.l.), located in Southeastern of Tibet Plateau, is the highest massif in the Hengduan Mountains and encompassed by three active faults, the Xianshuihe Fault, the Longmenshan Fault, and the Anninghe Fault. Dominated by regional monsoon climate, the Gongga massif surroundings have formed more than 70 temperate glaciers, which recently exhibit notable shrinkage due to their sensitivity to atmosphere warming. The Hailuogou Glacier is one of the most famous and touristed valley glaciers on the east slope of Mt. Gongga, with a 1080 m-high giant icefall connecting its upper accumulation basin and the lower debris-covered ice tongue. In recent years, extraordinary large-magnitude icefall avalanches were frequently reported by social media and cryosphere communities. The icefall demonstrates very conspicuous evidence of active flow of the Hailuogou Glacier. Since 2013, however, the icefall is gradually disconnected with its lower tongue, which thus loses the direct ice-flux transport from above and turns into a separate regenerated glacier. During summer, fast flowing ice in the upper stream of the icefall pushes the ice below moving downward and the ice blocks at the lowest part of the fractured icefall in general are readily to collapse.

The cover picture of the current issue of Journal of Mountain Science (Vol. 19, No. 11, 2022) shows Mt. Gongga and the upper Hailuogou Glacier accumulation area. This photo was taken by a drone hovering at an altitude of 5310 m a.s.l. on 03 August 2022, just one month before the Luding Earthquake, showing the supraglacial morphological characters and glacial ice structures of the area above the icefall. In this issue, the paper entitled “Stability of the Hailuogou glacier during the “9.5” Luding Earthquake: a preliminary assessment based on multi-source observations” checks the status and changes of the HLG glacier before, during and after the earthquake. The observed results show that the entire HLG glacier exhibited more stable than expected during the earthquake, with no abnormal change occurred in this upper accumulation part and only a small block of fractured ice at the lowest icefall collapsed. However, since the glacier valley has experienced remarkable downwasting and the paraglacial environment has been strongly disturbed and destabilized, systematically observations are necessary to monitor the regional glacier anomalies in this post-earthquake seismic active area.

封面故事

冰崩通常具有运动速度快、移动距离远等特征，极有可能诱发冰川作用区的山体滑坡、冰川泥石流、冰湖溃决洪水等链生灾害，造成灾难性的后果。近年来全球山地冰川失稳崩解的频率增加可能与大气变暖引起的冰冻圈边界条件变化（如冰川减薄、融水增加和冰缘冻土退化等）有关，同时也常常与它们相邻地域的地震活动扰动密切相关。

贡嘎山主峰海拔7556米，位于青藏高原东南部，是横断山最高峰，被鲜水河断裂、龙门山断裂和安宁河断裂三大活动断裂所环绕。贡嘎山地区受季风海洋型气候影响，周边发育了70多条海洋型温冰川。由于海洋型冰川对气候变暖更敏感，近年来冰川物质亏损显著。海螺沟冰川是贡嘎山东坡最著名的山谷冰川之一，其上部粒雪盆和下部表碛覆盖区冰舌之间以1080米高的巨大冰瀑布相连，而近年来发生在该冰瀑布的大规模冰崩事件频发，日益受到社会公众以及科学家的关注。冰瀑布是海螺沟冰川流动的明显证据，但从2013年开始，海螺沟冰川冰瀑布与下部冰舌逐渐断开，由于失去了来自上方的直接冰通量输送补给，冰舌段已逐渐成为一个独立的再生冰川。夏季在冰瀑上游快速流动的冰体推动下，位于冰瀑底部裂隙遍布的破碎冰体极易断裂崩塌而发生冰崩。

《山地科学学报（英文）》2022年第19卷第11期的封面照片显示的是位于贡嘎山东坡海螺沟冰川上游的积累区。照片是使用无人机在泸定地震前一个月（2022-08-02）在海拔5310米高空拍摄，展示了冰瀑上方地区冰川表面的形态特征和冰体结构。刘巧研究员及其团队在本期发表的“海螺沟冰川在“9.5”泸定地震中的稳定性:基于多源观测数据的初步评估”一文，对海螺沟冰川在震前、震中、震后的状态和变化进行了综合评估研究。观测结果表明，海螺沟冰川在此次地震过程中表现出比预期更稳定的状态，上游积累区部分基本没有发生异常变化，只有冰瀑布下游的一小块冰体发生了断裂崩塌引发了一次小规模冰崩。然而，由于近年来海螺沟冰川槽谷经历了明显的冰川减薄，两侧的冰缘边坡崩塌滑坡呈加剧趋势，加上地震的强烈扰动和不稳定加剧，震后有必要对该区域冰川异常进行系统观测，加强冰川相关灾害的风险评估与预警研究。

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