Antarctic icequakes triggered by the 2010 Maule earthquake in Chile
Antarctic icequakes triggered by the 2010 Maule earthquake in Chile
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DOI：
10.1038/ngeo2212
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发表时间：
2014-09-01
影响因子：
18.3
通讯作者：
Anandakrishnan, Sridhar
中科院分区：
文献类型：
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作者：
Peng, Zhigang;Walter, Jacob I.;Anandakrishnan, Sridhar
来自遥远的大地震的地震波在穿过地壳时几乎可以瞬间触发浅层微地震和深层构造震颤（1）。这种远程触发的地震活动大多发生在构造活动区。触发地震活动通常被认为反映了临界应力断层面上的剪切破坏，并被认为是由Love和Rayleigh类型的地表地震波的动态应力扰动驱动的（2）。在这里，我们分析了2010年智利马乌莱M-W 8.8地震前后六个小时内南极洲的地震数据。我们确定了许多高频地震信号的过程中产生的瑞利波的Maule地震，并解释为小冰震触发的瑞利波。这些触发冰震的震源位置很难确定，由于稀疏的地震台网覆盖，但触发事件产生的面波，所以可能是由近地表源。我们的观察结果是一致的拉伸断裂近地表冰或其他脆性断裂事件所造成的体积应变的变化作为高振幅的瑞利波通过。我们的结论是，冰冻圈系统可以是敏感的大型远距离地震。
Seismic waves from distant, large earthquakes can almost instantaneously trigger shallow micro-earthquakes and deep tectonic tremor as they pass through Earth's crust(1). Such remotely triggered seismic activity mostly occurs in tectonically active regions. Triggered seismicity is generally considered to reflect shear failure on critically stressed fault planes and is thought to be driven by dynamic stress perturbations from both Love and Rayleigh types of surface seismic wave(2). Here we analyse seismic data from Antarctica in the six hours leading up to and following the 2010 M-w 8.8 Maule earthquake in Chile. We identify many high-frequency seismic signals during the passage of the Rayleigh waves generated by the Maule earthquake, and interpret them as small icequakes triggered by the Rayleigh waves. The source locations of these triggered icequakes are difficult to determine owing to sparse seismic network coverage, but the triggered events generate surface waves, so are probably formed by near-surface sources. Our observations are consistent with tensile fracturing of near-surface ice or other brittle fracture events caused by changes in volumetric strain as the high-amplitude Rayleigh waves passed through. We conclude that cryospheric systems can be sensitive to large distant earthquakes.