Bimodal pattern of seismicity detected at the ocean margin of an Antarctic ice shelf
Bimodal pattern of seismicity detected at the ocean margin of an Antarctic ice shelf
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在南极冰架海洋边缘检测到的地震活动双峰模式
DOI：
10.1093/gji/ggw214
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发表时间：
2016
影响因子：
2.8
通讯作者：
C. Thom
中科院分区：
文献类型：
--
作者：
D. Lombardi;L. Benoit;T. Camelbeeck;O. Martin;C. Meynard;C. Thom
在南极洲，当地的冰，如冰上升边缘的浮动冰架，在冰的质量平衡中发挥着重要作用，因为它稳定了从内陆流入的冰盖。当与海洋直接接触时，冰升的支撑效应可能会随着海洋作用力的变化而改变。为了调查这一脆弱区域，2014年初，利用包括地震和全球定位系统传感器在内的新仪器，对南极洲东部德龙宁毛德地一个冰架边界附近的四个地点进行了为期一个月的监测。我们的研究表明，这一过渡带经历周期性的地震活动造成的表面裂缝在海洋潮汐引起的冰架破裂。最有意义的发现是在冰隆岬的向海前沿观测到明显的每两周潮汐调制低频、长持续时间的地震事件。假设这些事件的基底起源是在每次新的大潮时海水激增，触发当地基岩粗糙体的基底裂缝或基底滑动。对这种地震活动的探测和监测可能有助于确定易受强烈艾德海洋作用力影响的冰上升区。
In Antarctica, locally grounded ice, such as ice rises bordering floating ice shelves, plays a major role in the ice mass balance as it stabilizes the ice sheet flow from the hinterland. When in direct contact with the ocean, the ice rise buttressing effect may be altered in response of changing ocean forcing. To investigate this vulnerable zone, four sites near the boundary of an ice shelf with an ice rise promontory in Dronning Maud Land, East-Antarctica were monitored for a month in early 2014 with new instruments that include both seismic and GPS sensors. Our study indicated that this transition zone experiences periodic seismic activity resulting from surface crevassing during oceanic tide-induced flexure of the ice shelf. The most significant finding is the observation of apparent fortnightly tide-modulated low-frequency, long-duration seismic events at the seaward front of the ice rise promontory. A basal origin of these events is postulated with the ocean water surge at each new spring tide triggering basal crevassing or basal slip on a local bedrock asperity. Detection and monitoring of such seismicity may help identifying ice rise zones vulnerable to intensified ocean forcing.
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