Influence of volatile degassing on initial flow structure and entrainment during undersea volcanic fire fountaining eruptions
Influence of volatile degassing on initial flow structure and entrainment during undersea volcanic fire fountaining eruptions作者机构：Graduate School of Oceanography University of Rhode Island Narragansett USA University of Massachusetts Dartmouth Dartmouth USA
出 版 物：《Natural Science》 (自然科学期刊（英文）)
年 卷 期：2012年第4卷第12期
页 面：1002-1012页
学科分类：1002[医学-临床医学] 100214[医学-肿瘤学] 10[医学]
主 题：Subaqueous Volcanism Buoyant Eruption Fragmentation Submarine Fire Fountaining
摘 要：Release of dissolved volatiles during submarine fire fountaining eruptions can profoundly influence the buoyancy flux at the vent. Theoretical considerations indicate that in some cases buoyant magma can be erupted prior to fragmentation (~75% vesicle volume threshold). Laboratory simulations using immiscible fluids of contrasting density indicate that the structure of the source flow at the vent depends critically on the relative magnitudes of buoyancy and momentum fluxes as reflected in the Richardson number (Ri). Analogue laboratory experiments of buoyant discharges demonstrate a variety of complex flow structures with the potential for greatly enhanced entrainment of surrounding seawater. Such conditions are likely to favor a positive feedback between phreatomagmatic explosions and volatile degassing that will contribute to explosive volcanism. The value of the Richardson number for any set of eruption parameters (magma discharge rate and volatile content) will depend on water depth as a result of the extent to which the exsolved volatile components can expand.
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