Cyclic extrusion of a lava dome based on a stick-slip mechanism
Cyclic extrusion of a lava dome based on a stick-slip mechanism
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DOI：
10.1016/j.epsl.2012.05.011
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发表时间：
2012-07-01
影响因子：
5.3
通讯作者：
Melnik, O.
中科院分区：
文献类型：
--
作者：
Costa, A.;Wadge, G.;Melnik, O.
熔岩穹顶喷发的特点有时是挤出速度在几个小时内出现较大的周期性波动，并可能伴随着火山爆发和火山碎屑流。为了模拟这种短周期循环，我们考虑了一个简单的非线性方程组，该方程组描述了熔岩通过深弹性堤坝向浅层圆柱形管道输送的一维流动。在圆柱形管道的壁面边界上假定粘滑条件依赖于临界剪应力。与塑料挤出机中工业聚合物的行为类似，弹性堤坝的作用就像一个桶，管道较浅的圆柱形部分就像一个模子，让岩浆像聚合物一样流动。当我们将该模型应用于蒙特塞拉特的SouFriere Hills火山时，我们可以很容易地模拟出周期从3到30小时的循环挤压，与观测结果相匹配。该模型还再现了由于熔岩穹顶坍塌而发生重大卸荷事件时观察到的周期缩短的周期。皇冠版权所有(C)2012由爱思唯尔出版。保留所有权利。
Lava dome eruptions are sometimes characterised by large periodic fluctuations in extrusion rate over periods of hours that may be accompanied by Vulcanian explosions and pyroclastic flows. We consider a simple system of nonlinear equations describing a 1D flow of lava extrusion through a deep elastic dyke feeding a shallower cylindrical conduit in order to simulate this short-period cyclicity. Stick-slip conditions depending on a critical shear stress are assumed at the wall boundary of the cylindrical conduit. By analogy with the behaviour of industrial polymers in a plastic extruder, the elastic dyke acts like a barrel and the shallower cylindrical portion of the conduit as a die for the flow of magma acting as a polymer. When we applied the model to the Soufriere Hills Volcano, Montserrat, for which the key parameters have been evaluated from previous studies, cyclic extrusions with periods from 3 to 30 h were readily simulated, matching observations. The model also reproduces the reduced period of cycles observed when a major unloading event occurs due to lava dome collapse. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.