Analysis of the seismic activity associated with the 2010 eruption of Merapi Volcano, Java
Analysis of the seismic activity associated with the 2010 eruption of Merapi Volcano, Java
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DOI：
10.1016/j.jvolgeores.2013.03.024
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发表时间：
2013-07-01
影响因子：
2.9
通讯作者：
Metaxian, Jean-Philippe
中科院分区：
文献类型：
--
作者：
Budi-Santoso, Agus;Lesage, Philippe;Metaxian, Jean-Philippe
2010年的默拉皮火山喷发是用仪器观测到的第一次大规模爆炸性喷发。文中介绍并解释了喷发前地震活动的主要特征和这次地震危机。第一次地震前兆是喷发前12至4个月期间的一系列4个浅层震群。这些群被解释为由于热流增加而引起的水热系统扰动的结果。在2010年10月26日首次爆炸前约6周，开始了较短期和更持续的前兆地震活动。在此期间，地震活动的速率几乎不断增加，火山构造(VT)和多相事件(MP)的累积地震能量释放为7.5×10(10)J。这个值是默拉皮喷发之前最大能量释放的3倍。峰顶形变和地震活动达到的高度和加速行为是2010年火山喷发的显著特征。2010年VT地震的震中在峰顶以下2.5~5千米和小于1.5千米的深度内形成两个震群。在1.5-2.5公里的深度检测到了一个无震区，这与之前喷发的研究一致，表明这是默拉皮地下结构的一个强大特征。我们的分析表明，无震区是火山内部由蚀变物质组成的一层固结较差的层。深部VT事件主要发生在2010年10月17日之前；在此之后，浅层活动强烈增加。深部地震活动被解释为与异常大体积的快速上升的岩浆扩大了一条狭窄的管道有关。浅层地震活动被解释为记录了2010年10月26日触发喷发的顶穹顶塞的最终岩浆上升和破裂。利用根据原始记录计算的累积实时地震幅度(RSAM)和按主频分类的信号，应用重大破坏预测方法(FFM)对喷发发生时间进行事后预测。在喷发前6天的时间间隔内，对喷发时间的稳定估计误差小至+/-4小时。因此，在Merapi今后发生大规模爆炸性事件的情况下，这一办法可能有助于支持决策。(C)2013爱思唯尔B.V.保留所有权利。
The 2010 eruption of Merapi is the first large explosive eruption of the volcano that has been instrumentally observed. The main characteristics of the seismic activity during the pre-eruptive period and the crisis are presented and interpreted in this paper. The first seismic precursors were a series of four shallow swarms during the period between 12 and 4 months before the eruption. These swarms are interpreted as the result of perturbations of the hydrothermal system by increasing heat flow. Shorter-term and more continuous precursory seismic activity started about 6 weeks before the initial explosion on 26 October 2010. During this period, the rate of seismicity increased almost constantly yielding a cumulative seismic energy release for volcano-tectonic (VT) and multiphase events (MP) of 7.5 x 10(10) J. This value is 3 times the maximum energy release preceding previous effusive eruptions of Merapi. The high level reached and the accelerated behavior of both the deformation of the summit and the seismic activity are distinct features of the 2010 eruption.The hypocenters of VT events in 2010 occur in two clusters at of 2.5 to 5 km and less than 1.5 km depths below the summit. An aseismic zone was detected at 1.5-2.5 km depth, consistent with studies of previous eruptions, and indicating that this is a robust feature of Merapi's subsurface structure. Our analysis suggests that the aseismic zone is a poorly consolidated layer of altered material within the volcano. Deep VT events occurred mainly before 17 October 2010; subsequent to that time shallow activity strongly increased. The deep seismic activity is interpreted as associated with the enlargement of a narrow conduit by an unusually large volume of rapidly ascending magma. The shallow seismicity is interpreted as recording the final magma ascent and the rupture of a summit-dome plug, which triggered the eruption on 26 October 2010.Hindsight forecasting of the occurrence time of the eruption is performed by applying the Material Failure Forecast Method (FFM) using cumulative Real-time Seismic Amplitude (RSAM) calculated both from raw records and on signals classified according to their dominant frequency. Stable estimates of eruption time with errors as small as +/- 4 h are obtained within a 6 day lapse time before the eruption. This approach could therefore be useful to support decision making in the case of future large explosive episodes at Merapi. (C) 2013 Elsevier B.V. All rights reserved.