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波波卡特佩特火山爆炸式喷发活动是对周围人口稠密地区的一个严重威胁,因此在短时间内认识喷发类型(从爆炸式到熔岩盾形成)指标的变化是非常重要的。本次研究,我们给出来自波波卡特佩特火山5次主要普林尼式喷发(大约23~1.2ka)、2001年部分熔岩盾坍塌时的小喷发和1997年4次喷发(5月11日、6月14日、15日和30日)产生的原生碎屑中气孔大小分布(VSD)和基质玻璃成分分析的结果。对基质玻璃主元素的分析(WDS-EPMA)可以估计出喷发的岩浆进入不平衡(晶体和岩浆之间)的深度,通过利用Blundy和Cashman(2001)的石英-钠长石-正长石三元系计算平衡压力来获得。利用CSD软件通过气孔大小分布分析定量解释原生碎屑(浮岩或火山渣)结构来建立岩浆上升时的物理变化和喷发条件之间的关系。原生碎屑内气泡化的程度和类型也与喷发的类型和持续时间有关,特别是可用来识别气孔结构的变化,这种变化代表了从爆炸式到熔岩盾喷发的转变(Mangan and Sisson,2000;Adams et al,2006)。本次研究给出了波波卡特佩特火山比早期认为的更为复杂的岩浆存储历史,这对该火山目前的研究是一个重要的贡献。
The Popocatepet Volcanic Eruption is a serious threat to the surrounding densely populated areas, so it is important to recognize changes in the type of eruption (from explosive to lava shield formation) in a short period of time. In this study, we present five major Pliny eruptions (~ 23 ~ 1.2ka) from the Popocatepet volcano, small eruptions at the time of partial lava shield collapse in 2001 and four eruptions in 1997 (May 11 Day, June 14, 15, and 30) were used to analyze the results of pore size distribution (VSD) and matrix glass composition analysis in native debris. Analysis of major elements of matrix glass (WDS-EPMA) can estimate the depth at which eruptive magmas enter an imbalance (between crystals and magma) by using the quartz-albite-orthophite III of Blundy and Cashman (2001) Yuan system to calculate the equilibrium pressure to get. The relationship between the physical changes in the magma ascent and the eruption conditions was established by using the CSD software to quantitatively explain the structure of primary debris (pumic or volcanic debris) through the pore size distribution analysis. The degree and type of bubbling in native clasts is also related to the type and duration of eruptions and, in particular, to the changes in stomatal structure, which represent the transition from explosive to lava shield eruptions (Mangan and Sisson 2000 ; Adams et al, 2006). This study gives a more complicated magma storage history of Popocatepet than earlier thought, which is an important contribution to the present study of the volcano.