High‐speed imaging of Strombolian explosions: The ejection velocity of pyroclasts
High‐speed imaging of Strombolian explosions: The ejection velocity of pyroclasts
复制标题
斯特龙博利爆炸的高速成像：火山碎屑的喷射速度
DOI：
10.1029/2011gl050404
复制
发表时间：
2012
影响因子：
5.2
通讯作者：
U. Kueppers
中科院分区：
文献类型：
--
作者：
J. Taddeucci;P. Scarlato;A. Capponi;E. del Bello;C. Cimarelli;D. Palladino;U. Kueppers
爆炸性火山爆发被定义为从地壳的喷口猛烈喷出气体和热碎片。喷出速度的知识是至关重要的理解和建模有关的物理过程的喷发，但直接测量仍然是一项艰巨的任务，在很大程度上可变的结果。在这里，我们应用开创性的高速成像技术来测量Strombolian爆炸性喷发的火山碎屑的喷射速度，具有无与伦比的时间分辨率。测得的超音速高达405米/秒，比以前报告的这种喷发高出一倍。单个斯特龙博利爆炸包括多个亚秒持续的喷射脉冲，其特征在于速度的指数衰减。当与来自激波管实验文献的经验模型拟合时，这种衰减允许约束负责喷射脉冲的加压气体袋的长度。这些结果直接影响喷发建模和相关的灾害评估，以及对监测网络地球物理信号的解释。
Explosive volcanic eruptions are defined as the violent ejection of gas and hot fragments from a vent in the Earth's crust. Knowledge of ejection velocity is crucial for understanding and modeling relevant physical processes of an eruption, and yet direct measurements are still a difficult task with largely variable results. Here we apply pioneering high‐speed imaging to measure the ejection velocity of pyroclasts from Strombolian explosive eruptions with an unparalleled temporal resolution. Measured supersonic velocities, up to 405 m/s, are twice higher than previously reported for such eruptions. Individual Strombolian explosions include multiple, sub‐second‐lasting ejection pulses characterized by an exponential decay of velocity. When fitted with an empirical model from shock‐tube experiments literature, this decay allows constraining the length of the pressurized gas pockets responsible for the ejection pulses. These results directly impact eruption modeling and related hazard assessment, as well as the interpretation of geophysical signals from monitoring networks.