Waveform classification of volcanic low-frequency earthquake swarms and its implication at Soufriere Hills Volcano, Montserrat
Waveform classification of volcanic low-frequency earthquake swarms and its implication at Soufriere Hills Volcano, Montserrat
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DOI：
10.1016/j.jvolgeores.2005.08.003
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发表时间：
2006-05-01
影响因子：
2.9
通讯作者：
Neuberg, J
中科院分区：
文献类型：
--
作者：
Green, DN;Neuberg, J
低频率火山地震是岩浆在浅管道系统中迁移和活动的指示。在一些火山，这些事件表现出高度的波形相似性，提供了一个标准的分类。使用互相关技术来量化的相似程度，我们开发了一种方法来排序的事件到家庭包含可比的波形。一个系列内的事件在一个小的震源体积内被触发，然后地震波从该震源体积沿沿着相同的路径传播到接收器。1997年6月，在蒙特塞拉特火山苏弗里埃山，将这一方法应用于一系列16个低频地震群，这些地震群与倾斜仪记录的周期性变形有很好的相关性。确定了9个波形组，每个波形组包含超过45个事件。这些家族在群中重复，波形只有很小的变化。表明震源位置随时间稳定。低频率的地震群开始在膨胀开始减速之前，这表明地震活动表明，甚至开始减压过程。在所考虑的时间窗内发生了一次重大的圆顶倒塌，圆顶顶部100米被拆除。这一事件导致一些家庭的活动在重新出现之前暂停了几个周期。这表明坍塌并没有永久性地破坏震源机制或地震波的路径。(c)2005 Elsevier B.V.保留所有权利。
Low-frequency volcanic earthquakes are indicators of magma transport and activity within shallow conduit systems. At a number of volcanoes, these events exhibit a high degree of waveform similarity providing a criterion for classification. Using cross-correlation techniques to quantify the degree of similarity, we develop a method to sort events into families containing comparable waveforms. Events within a family have been triggered within one small source volume from which the seismic wave has then travelled along an identical path to the receiver. This method was applied to a series of 16 low-frequency earthquake swarms, well correlated with cyclic deformation recorded by tiltmeters, at Soufriere Hills Volcano, Montserrat, in June 1997. Nine waveform groups were identified containing more than 45 events each. The families are repeated across swarms with only small changes in waveform. indicating that the seismic source location is stable with time. The low-frequency seismic swarms begin prior to the point at which inflation starts to decelerate, suggesting that the seismicity indicates or even initiates a depressurisation process. A major dome collapse occurred within the time window considered, removing the top 100 m of the dome. This event caused activity within some families to pause for several cycles before reappearing. This shows that the collapse did not permanently disrupt the source mechanism or the path of the seismic waves. (c) 2005 Elsevier B.V. All rights reserved.