Triggering of volcanic degassing by large earthquakes
Triggering of volcanic degassing by large earthquakes
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DOI：
10.1130/g39074.1
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发表时间：
2017-08-01
期刊：
影响因子：
5.8
通讯作者：
Waite, Gregory P.
中科院分区：
文献类型：
--
作者：
Avouris, Dulcinea M.;Carn, Simon A.;Waite, Gregory P.
对大地震（M-w ≥ 7）和火山爆发之间时间关系的统计分析表明，地震波可能在距离震中很远（>1000 km）的地方触发火山爆发，但火山和火山活动之间的可靠关系仍然难以捉摸。在这里，我们调查的动态应力传播的表面波和火山的反应，表现在二氧化硫（SO2）排放量的变化由星载臭氧监测仪（OMI）之间的关系。对公元2004-2010年的69次地震的面波振幅进行了建模，这些地震发生在OMI检测到的12个持续脱气火山上。火山的反应进行了评估，检查每日OMI SO2测量值在28天的窗口集中在满足可变峰值动态应力阈值的地震。一个积极的火山反应，如果地震后的平均SO2质量至少比地震前的SO2质量大20%。我们发现两个不同的火山反应，强烈相关的喷发风格。开口玄武岩火山对地震产生的动态应力表现出积极的反应（即，地震触发增加的SO2排放），安山岩火山表现出负面反应。我们认为，前者是一致的中断或动员的气泡，或岩浆晃动，在低粘度的岩浆，而后者的观察可能反映更占主导地位的控制粘性岩浆脱气或地震后的渗透性降低。总的来说，这一分析表明，在解释火山气体排放趋势时，应考虑到大地震的潜在影响。
Statistical analysis of temporal relationships between large earthquakes (M-w >= 7) and volcanic eruptions suggests that seismic waves may trigger eruptions over great (>1000 km) distances from the epicenter, but a robust relationship between volcanic and teleseismic activity remains elusive. Here we investigate the relationship between dynamic stresses propagated by surface waves and a volcanic response, manifested by changes in sulfur dioxide (SO2) emissions measured by the spaceborne Ozone Monitoring Instrument (OMI). Surface wave amplitudes for a catalog of 69 earthquakes in A.D. 2004-2010 are modeled at 12 persistently degassing volcanoes detected by the OMI. The volcanic response is assessed by examining daily OMI SO2 measurements in 28 day windows centered on earthquakes meeting a variable peak dynamic stress threshold. A positive volcanic response is identified if the average post-earthquake SO2 mass was at least 20% larger than the pre-earthquake SO2 mass. We find two distinct volcanic responses, correlating strongly with eruption style. Open-vent, basaltic volcanoes exhibit a positive response to earthquake-generated dynamic stress (i.e., the earthquake triggers increased SO2 discharge), and andesitic volcanoes exhibit a negative response. We suggest that the former is consistent with disruption or mobilization of bubbles, or magma sloshing, in low-viscosity magmas, whereas the latter observation may reflect more dominant controls on degassing in viscous magmas or a post-earthquake reduction in permeability. Overall this analysis suggests that the potential effects of large earthquakes should be taken into account when interpreting trends in volcanic gas emissions.