On the formation of eruption columns following explosive mixing of magma and surface‐water
On the formation of eruption columns following explosive mixing of magma and surface‐water
复制标题
岩浆与地表水爆炸性混合后喷发柱的形成
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
A. Woods
中科院分区：
文献类型：
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作者：
T. Koyaguchi;A. Woods
当岩浆喷入大海或火山口湖时，随之而来的岩浆与水的相互作用可能会极大地影响喷发的方式。如果包含在喷发物质中的地表水质量很小(108公斤/S，高度随着地表水含量的增加而递减)。当岩浆和地表水开始构成柱顶质量的很大一部分时，就会发生这种情况，因此，越来越多的初始岩浆热能被转化为地表水，而不是夹带的空气。由于地表水与岩浆混合质量的变化而引起的喷发方式的转变，可能解释了1965年塔尔和1983年三宅岛喷发期间观测到的浮羽和湿涌浪，以及1963-1964年随着海水进入喷口变得更加限制而苏尔特西火山喷发活动的变化。我们还提出的计算表明，在湿流沉积中经常发现的吸积性青金石可能是由于冷湿坍塌喷泉中的水蒸气凝结和流动本身造成的。
When magma vents into the sea or a crater lake, the ensuing magma-water interaction can affect the style of eruption dramatically. If the mass of surface water incorporated into the erupting material is small, ( 108 kg/s, the height progressively decreases with surface water content. This occurs when the magma and surface water begin to constitute a significant fraction of the mass at the top of the column, so that an increasing fraction of the initial magmatic thermal energy is converted to the surface water rather than the entrained air. The transitions in eruption style which result from changes in the mass of surface water mixing with the magma may account for observations of both buoyant plumes and wet surge during the eruptions of Taal in 1965 and Miyake-jima in 1983 and for the changes in the eruptive activity at Surtsey in 1963–1964 as the access of seawater to the vent became more restricted. We also present calculations which suggest that the accretionary lapilli, which are often found in wet flow deposits, may result from condensation of vapor in both the cold, wet collapsing fountains and in the flows themselves.