Localised thickening and grounding of an Antarctic ice shelf from tidal triggering and sizing of cryoseismicity
Localised thickening and grounding of an Antarctic ice shelf from tidal triggering and sizing of cryoseismicity
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潮汐触发和冷震活动大小导致南极冰架局部增厚和接地
DOI：
10.1016/j.epsl.2018.09.024
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发表时间：
2018
影响因子：
5.3
通讯作者：
T. Dahm
中科院分区：
文献类型：
--
作者：
M. Pirli;S. Hainzl;J. Schweitzer;A. Köhler;T. Dahm
我们观察到显着的周期性模式的地震活动率和震级在芬布尔冰架，东南极洲，与海潮的周期。我们的分析涵盖了南极宽带台站19年的连续地震记录。2011年南半球夏季，在浅海区靠近海洋前缘的位置突然开始地震活动。数十个高度重复的事件以半日周期发生，其强度和速率随着潮汐而稳定波动。与地震震级普遍的不可预测性不同，地震震级在单周期内表现出确定性趋势，并与大潮和潮高有很强的相关性。事件发生准周期性和高度约束的事件源迁移在涨潮期间向陆地。我们表明，一个简单的力学模型可以解释大部分观察结果。我们的模型假设粘滑运动的补丁接地冰架，这是被迫的变化的海洋潮汐高度和冰流量。拟合良好的观测结果为地震摩擦触发的一般过程提供了新的见解，同时提供了冰架厚度和接地变化的独立证据。
We observe remarkably periodic patterns of seismicity rates and magnitudes at the Fimbul Ice Shelf, East Antarctica, correlating with the cycles of the ocean tide. Our analysis covers 19 years of continuous seismic recordings from Antarctic broadband stations. Seismicity commences abruptly during austral summer 2011 at a location near the ocean front in a shallow water region. Dozens of highly repetitive events occur in semi-diurnal cycles, with magnitudes and rates fluctuating steadily with the tide. In contrast to the common unpredictability of earthquake magnitudes, the event magnitudes show deterministic trends within single cycles and strong correlations with spring tides and tide height. The events occur quasi-periodically and the highly constrained event sources migrate landwards during rising tide. We show that a simple, mechanical model can explain most of the observations. Our model assumes stick-slip motion on a patch of grounded ice shelf, which is forced by the variations of the ocean-tide height and ice flow. The well fitted observations give new insights into the general process of frictional triggering of earthquakes, while providing independent evidence of variations in ice shelf thickness and grounding.
影响因子：
12.1
作者：
K. Matsuoka;R. Hindmarsh;G. Moholdt;M. J. Bentley;H. Pritchard;Joel Brown;H. Conway;R. Drews;G. Durand;D. Goldberg;T. Hattermann;J. Kingslake;J. Lenaerts;C. Martín;R. Mulvaney;K. Nicholls;F. Pattyn;N. Ross;T. Scambos;P. Whitehouse
通讯作者：
K. Matsuoka;R. Hindmarsh;G. Moholdt;M. J. Bentley;H. Pritchard;Joel Brown;H. Conway;R. Drews;G. Durand;D. Goldberg;T. Hattermann;J. Kingslake;J. Lenaerts;C. Martín;R. Mulvaney;K. Nicholls;F. Pattyn;N. Ross;T. Scambos;P. Whitehouse