Three‐dimensional investigation of volcanic textures by X‐ray microtomography and implications for conduit processes
Three‐dimensional investigation of volcanic textures by X‐ray microtomography and implications for conduit processes
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通过 X 射线显微断层扫描对火山纹理进行三维研究及其对管道过程的影响
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
F. Zanini
中科院分区：
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作者：
M. Polacci;D. Baker;L. Mancini;G. Tromba;F. Zanini
同步加速器X射线计算机显微断层扫描（μCT）首次应用于由活跃的爆炸性火山产生的浮石和火山渣碎屑，其特征是一系列喷发风格（温和的Strombolian到Plinian）和岩浆成分（玄武质到粗面质）。对获得的二维（2D）断层图像（对应于不同旋转角度的样品视图）进行处理，以重建三维（3D）体积，然后用于对囊泡度、囊泡数密度、体积和连通性进行3D测量，以定量表征所研究的火山灰。结果表明，泡的数量密度和喷发强度之间的正相关性，是用来调查岩浆脱气模式的爆发喷发。此外，囊泡的几何形状影响连接的气体流动路径的火山碎屑从Strombolian喷发的确定和相关的已知的渗透率。爆炸性喷发的动力学的影响进行了讨论，并最终用于定量区分不同的喷发风格。
Synchrotron X‐ray computed microtomography (μCT) was applied for the first time to clasts of pumice and scoria generated by active, explosive volcanoes characterized by a range of eruptive styles (mild Strombolian to Plinian) and magmatic composition (basaltic to trachytic). The obtained two‐dimensional (2D) tomographic images, corresponding to sample views at different rotation angles, were processed to reconstruct three‐dimensional (3D) volumes and then used to make 3D measurements of vesicularity, vesicle number density, volume and connectivity for quantitative characterization of the investigated tephras. The results indicate a positive correlation between vesicle number density and eruption intensity that is used to investigate modes of magma degassing in explosive eruptions. In addition, the vesicle geometry affecting the connected gas flow pathways in pyroclasts from Strombolian eruptions is determined and related to the known permeabilities. Implications on the dynamics of explosive eruptions is discussed and, ultimately, used to quantitatively discriminate between different eruptive styles.