First in-situ observation of a moving natural pyroclastic density current using Doppler radar
First in-situ observation of a moving natural pyroclastic density current using Doppler radar
复制标题
首次使用多普勒雷达对移动的天然火山碎屑密度流进行现场观测
DOI：
10.1038/s41598-019-43620-w
复制
发表时间：
2019
影响因子：
4.6
通讯作者：
N. Varley
中科院分区：
文献类型：
--
作者：
L. Scharff;M. Hort;N. Varley
火山碎屑密度流是最具破坏性的火山灾害之一。了解其动态是制定成功的减灾战略的关键。与火山碎屑密度流相关的危险通常是从其沉积物中事后研究的，或者是使用模拟和数值实验的先验研究。尽管观察到自然移动的火山碎屑密度流的概率很低，我们提出了第一个现场分析的火山碎屑密度流的内部粒子速度在Volcán de Colima使用多普勒雷达。我们的数据显示了两次火山爆发，紧接着是柱体坍塌和第一次火山碎屑密度流，以平均30米/秒（最大速度>50米/秒）的速度从南侧向下移动到距离火山口边缘3公里的地方。火山碎屑密度流的方向与雷达波束的方向一致，从而能够测量速度谱（雷达波束内粒子速度的直方图）。测量几何结构使得能够同时测量陨石坑边缘的密集暗流（小于20 m/s，回波功率在20 s以上增加）和接近雷达的地形上方的稀释云（大于20 m/s，回波功率近似恒定）。所提出的数据集可作为基准，为未来的实验和数值模型，模拟火山碎屑密度流的动态。使用测得的速度的倒塌柱作为输入的数值模型将允许验证的模型，预测的真实跳动距离，从而提供有价值的信息，危害评估。
Pyroclastic density currents are one of the most devastating volcanic hazards. Understanding their dynamics is a key to develop successful hazard mitigation strategies. The hazard associated with pyroclastic density currents is commonly investigated a posteriori from their deposits or a priori using analogue and numerical experiments. Despite the low probability of observing a natural moving pyroclastic density current, we present the first in-situ analysis of the internal particle velocities of pyroclastic density currents at Volcán de Colima using a Doppler radar. Our data show two Vulcanian explosions, immediately followed by column collapse and a first pyroclastic density current travelling down the south flank with an average speed of 30 m/s (>50 m/s maximum speed) to a distance of 3 km from the crater rim. The direction of the pyroclastic density current coincided with that of the radar beam enabling measurement of velocity spectra (histogram of particle velocities within the radar beam). The measurement geometry enables the simultaneous measurement of the dense undercurrent at the crater rim (with <20 m/s and an increasing echo power over 20 s) and the dilute cloud higher above the topography approaching the radar (with >20 m/s and approximately constant echo power). The presented data set may be used as a benchmark for future experimental and numerical models that simulate the dynamics of pyroclastic density currents. Using the measured velocities of the collapsing column as input for numerical models will permit the validation of the models for the prediction of the true run-out distance, and thus provide valuable information for hazard assessments.
使用多普勒雷达详细观察危地马拉圣地亚哥火山喷发云
影响因子：
--
作者：
Scharff;Ziemen;Johnson
通讯作者：
Johnson
危地马拉圣蒂亚吉托火山穹顶的动态
影响因子：
2.8
作者：
Scharff
通讯作者：
Scharff