Investigation into magma degassing at Nyiragongo volcano, Democratic Republic of the Congo
Investigation into magma degassing at Nyiragongo volcano, Democratic Republic of the Congo
复制标题
对刚果民主共和国尼拉贡戈火山岩浆脱气的调查
DOI：
10.1029/2007gc001829
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发表时间：
2008
期刊：
影响因子：
3.7
通讯作者：
M. Burton
中科院分区：
文献类型：
--
作者：
G. Sawyer;S. Carn;V. Tsanev;C. Oppenheimer;M. Burton
我们报告了通过地面遥感技术对尼拉贡戈火山排放的气体成分和流量的首次联合测量。2005年5月/6月和2006年1月进行的紫外光谱测量表明，二氧化硫的平均排放率分别为38 kg s-1和23 kg s-1。在2005年5月/6月、2006年1月和2007年6月获得的开路傅里叶变换红外光谱测量表明，H2O、CO2、SO2、CO、HCl、HF和OCS的平均摩尔比例分别为70、24、4.6、0.87、0.26、0.11和0.0016%。在2005年、2006年和2007年，烟羽的成分非常相似，CO2、SO2和CO的比例几乎没有时间变化，特别是在秒或天的尺度上，甚至在跨越24个月的三次实地活动之间。尽管山顶火山口的熔岩湖表面有各种各样的脱气行为（包括离散的斯特龙博利式爆发和熔岩喷泉）和二氧化硫排放率的变化，这种稳定性仍然存在。我们解释这些意见的一个制度的稳定状态脱气中，气泡成核和上升的对流岩浆的化学平衡。观察到SO2-HCl-HF组成的短期（秒至分钟）时间波动，这些波动归因于浅脱气过程。
We report the first combined measurements of the composition and flux of gas emitted from Nyiragongo volcano by ground‐based remote‐sensing techniques. Ultraviolet spectroscopic measurements made in May/June 2005 and January 2006 indicate average SO2 emission rates of 38 kg s−1 and 23 kg s−1, respectively. Open‐path Fourier transform infrared spectroscopic measurements obtained in May/June 2005, January 2006, and June 2007 indicate average molar proportions of 70, 24, 4.6, 0.87, 0.26, 0.11, and 0.0016% for H2O, CO2, SO2, CO, HCl, HF, and OCS, respectively. The composition of the plume was remarkably similar in 2005, 2006, and 2007, with little temporal variation in proportions of CO2, SO2, and CO, in particular, on the scale of seconds or days or even between the three field campaigns that span a period of 24 months. This stability persisted despite a wide range of degassing behaviors on the surface of the summit crater's lava lake (including discrete strombolian bursts and lava fountains) and variations in the SO2 emission rate. We explain these observations by a regime of steady state degassing in which bubbles nucleate and ascend in chemical equilibrium with the convecting magma. Short‐term (seconds to minutes) temporal fluctuations in the SO2–HCl–HF composition were observed, and these are attributed to shallow degassing processes.