Distal Enhanced Sedimentation From Volcanic Plumes: Insights From the Secondary Mass Maxima in the 1992 Mount Spurr Fallout Deposits
Distal Enhanced Sedimentation From Volcanic Plumes: Insights From the Secondary Mass Maxima in the 1992 Mount Spurr Fallout Deposits
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DOI：
10.1002/2017jb014412
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发表时间：
2017-10-01
影响因子：
3.9
通讯作者：
Wobrock, Wolfram
中科院分区：
文献类型：
--
作者：
Eychenne, Julia;Rust, Alison C.;Wobrock, Wolfram
一些火山灰沉降物在距离震源100公里处(次生质量最大区，ASMM)显示出质量和厚度的增加，这表明火山羽流的远端沉积作用增强。我们探索了1992年8月和9月美国斯珀尔火山喷发期间ASMMS的发展，方法是将质量和颗粒尺寸的空间分布与(1)单个粒子通过均匀和水平层结大气的模拟以及(2)包括下垫面地形影响的三维风场的中尺度模式相结合。沉积特征的横风向和顺风向变化表明，ASMMS的沉积增加并不完全是因为小颗粒的优先沉降(
Some tephra fallout deposits show an increase of mass and thickness at distances from the source >100km (areas of secondary mass maximum, ASMM) which demonstrates distal enhanced sedimentation from volcanic plumes. We explore development of the ASMMs during the 1992 August and September Mount Spurr eruptions, USA, by combining field data on the spatial distribution of mass and grain size with (1) simulations of individual particle settling through a homogeneous and horizontally stratified atmosphere and (2) mesoscale models of the three-dimensional wind field that include the effect of the underlying topography. The crosswind and downwind variations of deposit characteristics indicate that the increase of sedimentation at the ASMMs is not formed solely because of preferential settling of small ash particles (