Open and almost shut case for explosive eruptions: Vent processes determined by SO2 emission rates at Karymsky volcano, Kamchatka
Open and almost shut case for explosive eruptions: Vent processes determined by SO2 emission rates at Karymsky volcano, Kamchatka
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爆炸性喷发的开放和几乎封闭情况：堪察加卡雷姆斯基火山的 SO2 排放率决定的喷发过程
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
P. Kyle
中科院分区：
文献类型：
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作者：
T. Fischer;K. Roggensack;P. Kyle
在堪察加Karymsky火山，通过使用相关光谱仪（COSPEC）测量SO2排放量，对喷口过程进行了研究。1999年9月11日和12日，当Karymsky每5 - 20分钟产生一次小的火山灰喷发时，收集了连续的高灵敏度COSPEC测量和物理观测数据。每次喷发事件开始时都有爆炸和可听到的隆隆声（持续30秒），在某些情况下会有可听到的咔嗒声（持续2分钟）。气体羽流伴随着每一个事件，几乎无一例外地，羽流消散，变得不可见，尽管显着的二氧化硫排放。SO2输出的变化显示出与喷发活动相关的独特模式。最大的二氧化硫排放量发生在每次爆炸后，然后迅速下降到低，但可检测的水平。相比之下，第二种类型的事件，往往与可听的chugging，其特点是高二氧化硫输出后很长一段时间的初始灰爆炸。在Karymsky脱气的变化可以解释为二次沸腾，气体压力的积累，排气口重新密封。我们开发了COSPEC技术的一种新应用，以研究火山喷发的动态喷口过程。该应用程序提供了深入了解发生在火山喷发的火山口，否则无法进入的过程，特别是当火山从被动脱气和小爆炸到脱气模式的变化，可能会导致更大，更危险的喷发。
Vent processes were examined at Karymsky volcano, Kamchatka, by measuring SO2 emissions using a correlation spectrometer (COSPEC). Continuous high-sensitivity COSPEC measurements and physical observations were collected on 11 and 12 September 1999, when Karymsky was producing small ashy eruptions every 5‐20 min. Each eruptive event began with an explosion and audible rumbling (lasting ;30 s) followed in some cases by audible chugging (lasting to 2 min). Gas plumes accompanied each event, and almost without exception the plumes dissipated and became invisible despite significant SO2 emissions. Variations in SO2 output show distinctive patterns that correlate with eruption activity. Maximum SO2 output occurred following each explosion and then declined rapidly to low, but detectable levels. In contrast, a second type of event, often associated with audible chugging, was characterized by high SO2 output long after the initial ash blast. Variations in degassing at Karymsky can be explained by secondary boiling, gas-pressure accumulation, and vent resealing. We developed a new application of the COSPEC technique to study the dynamic vent processes of erupting volcanoes. This application provides insights into the processes that occur at the otherwise inaccessible vents of erupting volcanoes particularly when a volcano changes from passive degassing and small explosions to degassing patterns that may precede a larger and more dangerous eruption.