Local infrasound observations of large ash explosions at Augustine Volcano, Alaska, during January 11–28, 2006
Local infrasound observations of large ash explosions at Augustine Volcano, Alaska, during January 11–28, 2006
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2006 年 1 月 11 日至 28 日阿拉斯加奥古斯丁火山大规模火山灰爆炸的局部次声观测
DOI：
10.1029/2006gl026491
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发表时间：
2006
影响因子：
5.2
通讯作者：
S. McNutt
中科院分区：
文献类型：
--
作者：
T. Petersen;S. De Angelis;G. Tytgat;S. McNutt
我们介绍并解释了与2006年阿拉斯加奥古斯丁火山喷发初期发生的一系列大爆炸事件相关的声波波形。在2006年1月11日至28日期间，13起大爆炸事件产生了高达14公里的富含火山灰的烟羽，并产生了大气压力波，这些波由位于活动喷口3.2公里处的麦克风记录下来。记录到的各种波形包括持续时间为几秒的尖锐N形波、紧随其后的复杂尾波的脉冲信号，以及具有紧急特征和持续时间长达几分钟的扩展信号。峰值幅度在14至105pa之间变化；推断的声能在2×108至4×109J之间变化；2006年1月11日记录的一个简单的N形短持续时间信号与标志着爆炸序列开始的喷口打开爆炸有关。在接下来的几天里，伴随着脉冲起始点和延长尾声的波形伴随着喷发活动，其特点是爆炸事件产生了大量的火山灰云和沿火山侧翼的火山碎屑流。在此期间，缺乏清晰起搏的连续声波波形更为常见。2006年1月28日，奥古斯丁火山发生了四起大爆炸事件，标志着这一爆炸性喷发阶段的结束。经过大约两天的过渡期，以许多小的离散爆发为特征，喷发转变为更持续、更不具爆炸性的活动阶段，同时伴随着顶峰熔岩穹顶的重新增长。
We present and interpret acoustic waveforms associated with a sequence of large explosion events that occurred during the initial stages of the 2006 eruption of Augustine Volcano, Alaska. During January 11–28, 2006, 13 large explosion events created ash‐rich plumes that reached up to 14 km a.s.l., and generated atmospheric pressure waves that were recorded on scale by a microphone located at a distance of 3.2 km from the active vent. The variety of recorded waveforms included sharp N‐shaped waves with durations of a few seconds, impulsive signals followed by complex codas, and extended signals with emergent character and durations up to minutes. Peak amplitudes varied between 14 and 105 Pa; inferred acoustic energies ranged between 2 × 108 and 4 × 109 J. A simple N‐shaped short‐duration signal recorded on January 11, 2006 was associated with the vent‐opening blast that marked the beginning of the explosive eruption sequence. During the following days, waveforms with impulsive onsets and extended codas accompanied the eruptive activity, which was characterized by explosion events that generated large ash clouds and pyroclastic flows along the flanks of the volcano. Continuous acoustic waveforms that lacked a clear onset were more common during this period. On January 28, 2006, the occurrence of four large explosion events marked the end of this explosive eruption phase at Augustine Volcano. After a transitional period of about two days, characterized by many small discrete bursts, the eruption changed into a stage of more sustained and less explosive activity accompanied by the renewed growth of a summit lava dome.