A volcanic degassing event at the explosive-effusive transition
A volcanic degassing event at the explosive-effusive transition
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DOI：
10.1029/2007gl031379
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发表时间：
2007-11-14
影响因子：
5.2
通讯作者：
Herd, Richard A.
中科院分区：
文献类型：
--
作者：
Edmonds, Marie;Herd, Richard A.
2003年7月，苏弗里埃尔山火山的熔岩圆顶坍塌后，火山发生了五次连续爆炸。每次爆炸都发生在类似于t = 190 n（4.）其中n = 1 - 5，t是塌陷期间减压速率达到峰值后的时间。而不是在预测的时间发生第六次爆炸，光谱仪网络观察到97 x 10（3）kg SO2的快速排放。这一事件代表着从爆发性活动到热情洋溢活动的转变。在最后一次爆炸后，维持了高的岩浆上升速率，但没有达到临界超压爆炸标准。相反，脱气和结晶在上部管道引起的粘度和流速的水平梯度，和脆性破坏时的剪切应变率超过临界值的墙壁。渗透性剪切带的发展允许气体释放，超压的释放和溢流熔岩圆顶建筑的回归。
A sequence of five Vulcanian explosions followed a lava dome collapse in July 2003 at Soufrie` re Hills Volcano. Each explosion occurred at similar to t = 190 n (4.)3 where n = 1 - 5 and t is the time ( s) since the decompression rate peak during the collapse. Instead of a sixth explosion at the predicted time, a rapid emission of 97 x 10(3) kg SO2 was observed by a spectrometer network. This event represents the transition from explosive to effusive activity. After the last explosion, high magma ascent rates were maintained, but the critical overpressure explosion criterion was not reached. Instead, degassing and crystallisation in the upper conduit caused horizontal gradients in viscosity and flow rate, and brittle failure at the walls when the rate of shear strain exceeded a critical value. Development of a permeable shear zone allowed gas release, relief of overpressure and a return to effusive lava- dome building.