Tidally Modulated Glacial Slip and Tremor at Helheim Glacier, Greenland
Tidally Modulated Glacial Slip and Tremor at Helheim Glacier, Greenland
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DOI：
10.1029/2023gl105342
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发表时间：
2024-01-16
影响因子：
5.2
通讯作者：
Xie，Surui
中科院分区：
文献类型：
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作者：
Yan，Peng;Holland，David M.;Xie，Surui
冰盖运动的数值模拟以及全球海平面上升的预估需要关于冰下环境演变的信息，不幸的是，由于难以获得这些信息，这些信息在很大程度上仍然是未知的。在这里，我们通过报道可能与Helheim冰川滑动有关的地震的多年观测来推进这种冰下观测。在不同的时间尺度上，地震功率与多种环境力的相关分析证实了这种关联。观测到的震动功率的变化表明不同的因素在不同的时间尺度上影响冰川滑动。有效压力可以在长（季节/年）时间尺度上控制冰川滑动，而潮汐强迫在短（小时/日）时间尺度上调节滑动速率和震动功率。极化结果表明震源来自上游的冰下脊。这一观测结果为如何将不同的因子纳入冰盖模拟以及它们的变率时间尺度如何发挥重要作用提供了见解。
Numerical modeling of ice sheet motion and hence projections of global sea level rise require information about the evolving subglacial environment, which unfortunately remains largely unknown due to its difficulty of access. Here we advance such subglacial observations by reporting multi‐year observations of seismic tremor likely associated with glacier sliding at Helheim Glacier. This association is confirmed by correlation analysis between tremor power and multiple environmental forcings on different timescales. Variations of the observed tremor power indicate that different factors affect glacial sliding on different timescales. Effective pressure may control glacial sliding on long (seasonal/annual) timescales, while tidal forcing modulates the sliding rate and tremor power on short (hourly/daily) timescales. Polarization results suggest that the tremor source comes from an upstream subglacial ridge. This observation provides insights on how different factors should be included in ice sheet modeling and how their timescales of variability play an essential role.