Forecasting the timing and size of volcanic eruptions requires a proper interpretation of multiparametric monitoring signals. Studies of the erupted rocks can provide critical information on the processes and volcano plumbing system that is needed to decode the monitoring signals. Here we present the results of a petrological study of plagioclase phenocrysts using a new statistical approach that allows us to estimate the amount of intruded magma before eruption. Our crystal population analysis of the 2006 and 2010 CE Merapi volcano (Indonesia) eruptions shows that ∼60 ± 20 vol% of the 2010 magma was left over from the 2006 magma, and thus ∼40 ± 20 vol% was newly intruded magma. Using the published values of the 2010 erupted magma volume, this corresponds to >8 to 20 (±7) × 106 m3 of new magma. This is a minimum estimate and is similar to the inferred pre-eruptive deformation volume (18 × 106 m3), although given the uncertainties, several million cubic meters of magma intruded in 2010 could still be in the Merapi plumbing system. Our approach could be used at other volcanoes to quantify the volume of intruded magma and thus help in better understanding the unrest signals that anticipate eruptions. INTRODUCTION Many volcanoes erupt magmas of the same composition for decades or centuries, e.g., Mayon in the Philippines (Newhall, 1979), Merapi in Indonesia (Costa et al., 2013), Arenal in Costa Rica (Reagan et al., 1987), or Soufrière Hills in Montserrat (Murphy et al., 2000). What drives these frequent eruptions of the same magma? How much of the magma produced by each eruption is new replenishment, and how much was already stored in the system? Being able to answer these questions is important for understanding how volcanos work, and thus for being able to properly interpret monitoring data and

中文翻译：

---

晶体种群的统计分析和与火山变形的联系，以更可靠地估计岩浆补充量

预测火山爆发的时间和规模需要正确解释多参数监测信号。对喷发岩石的研究可以提供有关解码监测信号所需的过程和火山管道系统的关键信息。在这里，我们使用一种新的统计方法展示了斜长石斑晶的岩石学研究结果，该方法使我们能够估计喷发前侵入的岩浆量。我们对 2006 年和 2010 年 CE 默拉皮火山（印度尼西亚）喷发的晶体群分析表明，2010 年岩浆中约有 60 ± 20 vol% 是 2006 年岩浆遗留下来的，因此约 40±20 vol% 是新侵入的岩浆。使用 2010 年喷发岩浆体积的公布值，这对应于 >8 到 20 (±7) × 106 m3 的新岩浆。这是最小估计值，类似于推断的喷发前变形体积（18 × 106 立方米），尽管考虑到不确定性，2010 年侵入的数百万立方米岩浆可能仍存在于默拉皮管道系统中。我们的方法可用于其他火山，以量化侵入岩浆的体积，从而有助于更好地了解预测喷发的动荡信号。简介 许多火山喷发了几十年或几个世纪以来成分相同的岩浆，例如菲律宾的马荣火山（Newhall，1979）、印度尼西亚的默拉皮火山（Costa 等，2013）、哥斯达黎加的阿雷纳尔（Reagan 等，1987） ，或蒙特塞拉特的 Soufrière Hills（墨菲等，2000）。是什么驱动了同一岩浆的这些频繁喷发？每次喷发产生的岩浆有多少是新的补充，系统中已经存储了多少？能够回答这些问题对于理解火山的工作原理很重要，从而能够正确解释监测数据和