Climate change is increasingly predisposing polar regions to large landslides. Tsunamigenic landslides have occurred recently in Greenland ( Kalaallit Nunaat ), but none have been reported from the eastern fjords. In September 2023, we detected the start of a 9-day-long, global 10.88-millihertz (92-second) monochromatic very-long-period (VLP) seismic signal, originating from East Greenland. In this study, we demonstrate how this event started with a glacial thinning–induced rock-ice avalanche of 25 × 10 6 cubic meters plunging into Dickson Fjord, triggering a 200-meter-high tsunami. Simulations show that the tsunami stabilized into a 7-meter-high long-duration seiche with a frequency (11.45 millihertz) and slow amplitude decay that were nearly identical to the seismic signal. An oscillating, fjord-transverse single force with a maximum amplitude of 5 × 10 11 newtons reproduced the seismic amplitudes and their radiation pattern relative to the fjord, demonstrating how a seiche directly caused the 9-day-long seismic signal. Our findings highlight how climate change is causing cascading, hazardous feedbacks between the cryosphere, hydrosphere, and lithosphere.

中文翻译：

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格陵兰峡湾的岩石滑坡引发的海啸使地球持续了 9 天


气候变化越来越使极地地区容易发生大型山体滑坡。格陵兰岛 （Kalaallit Nunaat） 最近发生了引发海啸的山体滑坡，但东部峡湾尚未报告。2023 年 9 月，我们探测到一个源自东格陵兰岛的为期 9 天的全球 10.88 毫赫兹（92 秒）单色超长周期 （VLP） 地震信号的开始。在这项研究中，我们展示了这一事件是如何以冰川变薄引发的 25 × 10 6 立方米的岩冰雪崩开始的，该雪崩坠入迪克森峡湾，引发了 200 米高的海啸。模拟显示，海啸稳定成 7 米高的长持续时间地震，频率（11.45 毫赫兹）和缓慢的振幅衰减与地震信号几乎相同。最大振幅为 5 × 10 11 牛顿的振荡峡湾横向单力再现了地震振幅及其相对于峡湾的辐射模式，展示了地震如何直接引起长达 9 天的地震信号。我们的研究结果强调了气候变化如何导致冰冻圈、水圈和岩石圈之间的级联危险反馈。