Pulsed Vulcanian explosions: A characterization of eruption dynamics using Doppler radar
Pulsed Vulcanian explosions: A characterization of eruption dynamics using Doppler radar
复制标题
DOI：
10.1130/g36705.1
复制
发表时间：
2015-11
期刊：
影响因子：
5.8
通讯作者：
L. Scharff;M. Hort;N. Varley
中科院分区：
文献类型：
--
作者：
L. Scharff;M. Hort;N. Varley
了解正在进行的火山喷发的动态对于预测火山灰在大气中的输入和输送至关重要。为了限制火山喷口附近爆炸事件的动态过程，我们在科利马火山（墨西哥）和圣地亚哥吉托（危地马拉）的两个现场实验中使用多普勒雷达测量，提供火山灰速度和质量通量代理。我们发现两座火山的爆发性喷发均由单独的脱气脉冲组成。对此类脉冲时间的分析表明，两座火山的首选脉冲间隔时间分别为 3 秒（圣地亚哥）和 2-5 秒（科利马火山）。一个事件期间的脉冲间时间可能会改变，但通常会返回到首选的脉冲间时间。这种行为在两个火山上都是相似的，并且脉冲间时间大致遵循对数逻辑分布，表明两个竞争过程的相互作用。这些可能是最上面管道的短期脱气与由于喷发过程中气体逐渐流失和压实而导致的渗透性降低。
Understanding the dynamics of ongoing volcanic eruptions is essential for predicting the input and transport of volcanic ash in the atmosphere. To constrain near-vent dynamic processes of explosive Vulcanian events, we used Doppler radar measurements, providing tephra velocities and a proxy of the mass flux, in two field experiments at Volcan de Colima (Mexico) and Santiaguito (Guatemala). We find that explosive eruptions at both volcanoes consist of individual degassing pulses. The analysis of the timing of such pulses shows that both volcanoes have preferred interpulse times of 3 s (Santiaguito) and 2–5 s (Volcan de Colima). The interpulse time during one event may change, but it often returns to the preferred interpulse time. This behavior is similar at both volcanoes and the interpulse time roughly follows a log-logistic distribution indicating the interplay of two competing processes. These could be short-duration degassing of the uppermost conduit versus decreasing permeability due to progressive gas loss and compaction during an eruption.