Resonances of a volcanic conduit triggered by repetitive injections of an ash‐laden gas
Resonances of a volcanic conduit triggered by repetitive injections of an ash‐laden gas
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重复注入含灰气体引发的火山管道共振
DOI：
10.1029/2003gl018934
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发表时间：
2003
影响因子：
5.2
通讯作者：
H. Yepes
中科院分区：
文献类型：
--
作者：
I. Molina;H. Kumagai;H. Yepes
2001年12月，在厄瓜多尔安山岩层状火山通古拉瓦火山喷发活动加剧之前，记录了一系列长周期地震事件。LP事件呈现简单的衰减简谐振荡，频率范围为2~3.5赫兹，品质因数(Q)明显大于100。我们对LP事件的频谱分析确定了LP事件的频率和Q的系统性时间变化。假设在LP事件的源处有一个裂纹谐振器，可以通过增加谐振器内的灰分含量来一致地解释这种时间变化，这可能是因为作为喷发的准备过程，将富含灰分的气体重复注入到管道中预先存在的裂缝中。
A swarm of long‐period (LP) seismic events was recorded in December 2001 before heightened eruptive activity of Tungurahua Volcano, an andesitic stratovolcano in Ecuador. The LP events showed simple decaying harmonic oscillations with frequencies ranging from 2 to 3.5 Hz and quality factors (Q) significantly larger than 100. Our spectral analysis of the LP events identified systematic temporal variations in both frequency and Q of the LP events. Assuming a crack resonator at the source of LP events, the temporal variations can be consistently explained by increasing the ash content within the resonator, which may be caused by repetitive injections of an ash‐laden gas into a pre‐existing crack in the conduit as a preparatory process for eruptions.