近日，美国阿拉斯加费尔班克斯大学Jamshid A. Moshrefzadeh团队研究了2006年阿拉斯加州奥古斯丁火山爆发前，利用晶体凝块的溶解表面来量化压力变化。2025年5月29日出版的《地质学》发表了这项成果。

量化火山系统中爆发前超压的积聚对于理解爆发触发机制至关重要。阿拉斯加奥古斯汀火山2006年的喷发为研究富含晶体的中等寄主岩浆中的晶体对喷发前不久镁铁质补给引起的温度和压力扰动的反应提供了绝佳的机会。研究组使用斜长石的成分变化以及相邻和同时生长的斜方辉石来量化岩浆条件对这种补给事件的反应。 

结果发现，斜长石中钙长石含量增加3.9 mol%，最好用2006年喷发前岩浆压力增加7.7 MPa（0.4-37 MPa，80%不确定性界限）来解释。该值接近岩石的估计抗拉强度，表明镁铁质补给引起的压力增加可能足以引发岩脉侵入，并可能引发火山爆发。这种方法可以在富含晶体、中等和含水的弧形火山上广泛实施，可以提供喷发前压力变化的独立估计，以补充地球物理模型，并可以为导致火山爆发的物理过程提供新的见解。

附：英文原文

Title: Using dissolution surfaces in crystal clots to quantify pressure changes preceding the 2006 eruption of Augustine Volcano, Alaska

Author: Valerie K. Wasser, Pavel E. Izbekov, Taryn M. Lopez, Nathan A. Graham, Jamshid A. Moshrefzadeh

Issue&Volume: 2025-05-29

Abstract: Quantifying the buildup of pre-eruptive excess pressure in volcanic systems is crucial for the understanding of eruption-triggering mechanisms. The 2006 eruption of Augustine Volcano, Alaska, provides an excellent opportunity to investigate the response of the crystal cargo within a crystal-rich, intermediate host magma to temperature and pressure perturbations induced by mafic recharge shortly before the eruption. We use compositional changes of plagioclase together with adjoined and concurrently grown orthopyroxene to quantify these changes in magma conditions in response to this recharge event. We find ～3.9 mol% anorthite increase in plagioclase is best explained by a 7.7 MPa (0.437 MPa, 80% uncertainty bounds) increase in magmatic pressure prior to the 2006 eruption. This value is close to the estimated tensile strength of rocks, suggesting that the pressure increase due to mafic recharge was likely sufficient to initiate dike intrusion and possibly trigger the eruption. This approach can be implemented broadly at crystal-rich, intermediate, and hydrous arc volcanoes, can provide independent estimates of pre-eruptive pressure changes to complement geophysical models, and can add new insights into the physical processes that lead to volcanic eruptions.

DOI: 10.1130/G52976.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G52976.1/654870/Using-dissolution-surfaces-in-crystal-clots-to