Correlations between SO2 flux, seismicity, and outgassing activity at the open vent of Villarrica volcano, Chile
Correlations between SO2 flux, seismicity, and outgassing activity at the open vent of Villarrica volcano, Chile
复制标题
智利比亚里卡火山露天喷口的 SO2 通量、地震活动和放气活动之间的相关性
DOI：
10.1029/2008jb005577
复制
发表时间：
2008
影响因子：
--
通讯作者：
D. Rothery
中科院分区：
文献类型：
--
作者：
J. L. Palma;E. Calder;D. Basualto;S. Blake;D. Rothery
[1]通过对智利比利亚里卡火山熔岩湖的目视观测、地震分析和SO2通量的测量，详细研究了该火山开口喷口活动的特征。除气活动包括从陨石坑底部持续排放的气体羽流以及频繁的爆炸事件。在活跃的熔岩湖表面，发现了三种主要的气泡破裂方式：沸腾的岩浆、小型短命的熔岩喷泉和斯特龙博利爆炸。沸腾的岩浆由相对较小的气泡（直径几米）的连续破裂组成，这些气泡在熔岩湖的整个表面上具有不同的强度。小型熔岩喷泉，被视为沸腾岩浆的有力延伸，通常持续时间为20-120秒，高出熔岩湖10-40米。地震活动与目视观测的相关性表明，地震震颤主要是由爆炸放气活动引起的。此外，对于2000年至2006年的不同时期，在此期间，活动保持可比性，实时地震振幅测量系统（RSAM）和二氧化硫排放率显示出很好的相关性。较高的二氧化硫排放量似乎与较高水平的熔岩湖，更强的气泡破裂活动，以及火山口底部的形态和纹理的变化有关。背景（低）活动水平对应于位于火山口边缘以下>80米的熔岩湖，屋顶的小和/或块状形态，地震振幅（RSAM）低于25个单位，少数火山构造地震，以及SO2排放量的日平均值低于600毫克/天。
[1] The characteristics of the open vent activity of Villarrica volcano, Chile, were studied in detail by integrating visual observations of the lava lake, analysis of the seismic tremor, and measurements of SO2 flux. The outgassing activity comprises a persistent gas plume emission from the bottom of the crater as well as frequent explosive events. Three main styles of bubble bursting were identified at the surface of the active lava lake: seething magma, small short-lived lava fountains, and Strombolian explosions. Seething magma consists of continual burst of relatively small bubbles (a few meters in diameter) with varying strength over the entire surface of the lava lake. Small lava fountains, seen as a vigorous extension of seething magma, commonly have durations of 20–120 s and reach 10–40 m high above the lava lake. Correlations between seismicity and visual observations indicate that the seismic tremor is mostly caused by the explosive outgassing activity. Furthermore, for different periods between 2000 and 2006, during which the activity remained comparable, the real-time seismic amplitude measurement system (RSAM) and SO2 emission rates show a very good correlation. Higher SO2 emissions appeared to be related to higher levels of the lava lake, stronger bubble bursting activity, and changes in the morphology and texture of the crater floor. Background (low) levels of activity correspond to a lava lake located >80 m below the crater rim, small and/or blocky morphology of the roof, seismic amplitude (RSAM) lower than 25 units, few volcano-tectonic earthquakes, and daily averages of SO2 emissions lower than 600 Mg/d.