THERMAL CONTROL OF BASALTIC FISSURE ERUPTIONS
THERMAL CONTROL OF BASALTIC FISSURE ERUPTIONS
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DOI：
10.1038/342665a0
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发表时间：
1989-12-07
期刊：
影响因子：
64.8
通讯作者：
HUPPERT, HE
中科院分区：
文献类型：
--
作者：
BRUCE, PM;HUPPERT, HE
火山喷发时，炽热的玄武岩岩浆从新开的岩脉中升起，流过较冷的地壳岩石。流动的岩浆沿岩脉将热量平流；与此同时，热量从堤坝传导到更冷的环境中。热量的损失最初会导致通道因岩浆在壁上凝固而变得狭窄。然后，通道可能会被完全堵塞，这将在岩浆供应耗尽之前结束该地点的喷发。另一种情况是，经过一段时间后，流动的岩浆持续提供的热量可能超过岩石中的热量损失。在这种情况下，最初的凝固被逆转，沟道壁逐渐融化，堤防被加宽，直到供应减少。我们在这里提出了一个定量描述这两种制度的模型。我们还确定了一种中间状态，在这种状态下，部分地表裂缝可能被阻塞，火山喷发从孤立的喷口继续进行。
As hot, basaltic magma rises in a newly opened dyke during an eruption, it flows through colder crustal rock. The flowing magma advects heat along the dyke; at the same time, heat is conducted out of the dyke into the colder surroundings. The loss of heat will lead initially to the channel becoming constricted by magma solidifying against the walls. The channel may then become completely blocked, which will end the eruption at that site before the supply of magma is exhausted. Alternatively, the continual supply of heat by the flowing magma may, after some time, exceed the losses into the country rock. In this case, the initial solidification is reversed, the walls of the channel are progressively melted and the dyke is widened until the supply diminishes. We present here a model that quantitatively delineates these two regimes. We also identify an intermediate regime in which parts of the surface fissure may become blocked and the eruption continues from isolated vents.