2011年卡特拉火山的动荡：震颤源的表征和解释
The 2011 unrest at Katla volcano: characterization and interpretation of the tremor sources
摘要：
2011年7月8日至9日，卡特拉冰下火山（Katla subglacial volcano）记录了一次长达23小时的地震爆发，这是冰岛最活跃和最危险的火山之一。这与冰盖上的坩埚加深和冰川洪水对基础设施造成的破坏有关。火山口内的地震活动在几天前开始增加，并持续了几个月之后，新的地震活动性开始在南侧。没有可见的喷发打破了冰，问题是这一事件是否与一个小的冰下喷发有关，地震是由火山过程或洪水产生的。震颤信号由具有不同幅度和持续时间的突发组成。我们已经确定并描述了三个不同的震颤阶段，振幅和频率的基础上的功能。与洪水相关的震颤阶段仅在最靠近洪水泛滥的河流的站点记录，与测量站观察到的水位上升及时相关。使用反向投影的双重互相关，其他两个阶段已位于附近的活跃的冰大锅，并解释为火山或热液过程所造成的。大幅度增加的地震活动和冰川快速融化的证据可能是由一个小的冰下喷发解释。还有一种可能性是，地震是由热液沸腾和/或爆炸产生的，没有岩浆参与。这可能是由冰川洪水开始时释放的水引发的压力下降引起的。所有的解释都需要火山释放的热量增加。
英文摘要：
A 23 hour tremor burst was recorded on July 8-9th 2011 at the Katla subglacial volcano, one of the most active and hazardous volcanoes in Iceland. This was associated with deepening of cauldrons on the ice cap and a glacial flood that caused damage to infrastructure. Increased earthquake activity within the caldera started a few days before and lasted for months afterwards and new seismic activity started on the south flank. No visible eruption broke the ice and the question arose as to whether this episode relates to a minor subglacial eruption with the tremor being generated by volcanic processes, or by the flood. The tremor signal consisted of bursts with varying amplitude and duration. We have identified and described three different tremor phases, based on amplitude and frequency features. A tremor phase associated with the flood was recorded only at stations closest to the river that flooded, correlating in time with rising water level observed at gauging stations. Using back-projection of double cross-correlations, two other phases have been located near the active ice cauldrons and are interpreted to be caused by volcanic or hydrothermal processes. The greatly increased seismicity and evidence of rapid melting of the glacier may be explained by a minor sub-glacial eruption. It is also plausible that the tremor was generated by hydrothermal boiling and/or explosions with no magma involved. This may have been induced by pressure drop triggered by the release of water when the glacial flood started. All interpretations require an increase of heat released by the volcano.
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