Dynamics of the 1902 Eruptions of Montagne Pelee Determined from Size, Shape, and Textures of Vitric Pyroclasts

该项目将研究1902年Pelee火山灾难性喷发产生的nuee-ardente沉积物中的幼年玻璃状火山，作为解释这一活动循环中火山喷发动力学中流体火山作用的基础。这项研究是专门为了对造成如此大规模和毁灭性的爆炸性喷发的物理过程提供更清晰的见解。电子探针（EMP）、扫描电子显微镜（SEM）、图像分析和尺寸分布分析将成为研究马蒂尼克岛圣皮埃尔附近连续火山活动或沉积物重力流所留下的麻风沉积物的主要技术。对幼龄玻璃质碎屑的内部和表面结构信息的观测将揭示(1)幼龄岩浆挥发物注入导致的岩浆泡泡化和破碎过程；(2)岩浆活动在喷发过程中的作用和时间；(3)新语的起源；(4)核-热固性颗粒在输运和沉积过程中的相互作用机理。利用序贯破碎和输运的新模型进行粒度分布分析，可以确定离源不同距离的不同区域破碎和输运过程的成熟度。这一信息对于评估具有大喷发历史的火山（如佩利山火山）的火山危险性非常有用。

This project will investigate juvenile glassy tephra from the nuee-ardente deposits produced the cataclysmic eruptions on Montagne Pelee in 1902, as a basis for interpretation of the role of hydrovolcanism in the eruption dynamics of this cycle of activity. The research is undertaken specifically to provide sharper insights into the physical processes responsible for such large and devastating explosive eruptions. Electron microprobe (EMP), scanning electron microscope (SEM), image analysis, and size distribution analysis will be the main techniques used to investigate tephra deposits left by the passage of successive nuees ardentes or sediment gravity flows in the vicinity of St. Pierre, Martinique. Internal and surficial textural information observed on juvenile vitric fragments from the nuee ardente deposits will shed light on (1) processes of magma vesiculavesiculation and fragmentamentation as a result of sion of juvenile magmatic volatiles; (2) the role and timing of hydromagmatism during the eruption; (3) the genesis of nuee ardentes; and (4) the mechanics of particle-particle interaction during transtransport and deposition of nuee-ardente tephra. Grain size distribution analysis using the new model of sequential fragmentation and transport will allow the identification of maturity of fragmentation and transportation processes to be evaluated for various parts of the nuees at various distances from the source. This information should be extremely useful in the evaluation of volcanic hazards at volcanoes with a history of large expolosions such as those of Montagne Pelee.