气候变化领域集成服务门户(CCPortal): Brittle fragmentation by rapid gas separation in a Hawaiian fountain

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DOI	10.1038/s41561-021-00709-0
	Brittle fragmentation by rapid gas separation in a Hawaiian fountain
	Namiki A.; Patrick M.R.; Manga M.; Houghton B.F.
发表日期	2021
ISSN	17520894
起始页码	242
结束页码	247
卷号	14 期号:4
英文摘要	Brittle fragmentation, generating small pyroclasts from magma, is a key process determining eruptive style. How low-viscosity magma fragments within a rising fountain in a brittle manner, however, is not well understood. Here we describe a fragmentation process in Hawaiian fountains on the basis of observations from the 2018 lower East Rift Zone eruption of Kīlauea Volcano, Hawai’i. The dominant fragmentation mechanism is inertia driven and produces a population of large fluidal pyroclasts. However, when sufficient volcanic gas is released in the fountain, a subpopulation of smaller and more vesicular pyroclasts is generated and entrained into the gas-dominant convective plume. The size distribution of these pyroclasts is similar to that of brittlely fragmented solid materials. The erupted high-vesicularity pyroclasts sometimes preserve a deformed shape. These observations suggest that late-stage rapid expansion lowers the gas temperature adiabatically and cools the outer surface of liquid pyroclasts below the glass transition temperature. The rigid crust fragments as the hot interior attempts to expand due to further volatile diffusion from the melt into bubbles. Adiabatic expansion of volcanic gas occurs in all eruptions. Brittle fragmentation induced by rapid adiabatic cooling may be a widespread process, although of varying importance, in explosive eruptions. © 2021, The Author(s), under exclusive licence to Springer Nature Limited part of Springer Nature.
英文关键词	cooling water; explosive; Kilauea; pyroclastic deposit; separation; temperature effect; volcanic eruption; volcanic gas
语种	英语
来源期刊	Nature Geoscience
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/206940
作者单位	Graduate School of Environmental Studies, Nagoya University, Nagoya, Japan; US Geological Survey, Hawaiian Volcano Observatory, Hilo, HI, United States; Department of Earth and Planetary Science, UC Berkeley, Berkeley, CA, United States; Department of Earth Sciences, University of Hawaii, Honolulu, HI, United States
推荐引用方式 GB/T 7714	Namiki A.,Patrick M.R.,Manga M.,et al. Brittle fragmentation by rapid gas separation in a Hawaiian fountain[J],2021,14(4).
APA	Namiki A.,Patrick M.R.,Manga M.,&Houghton B.F..(2021).Brittle fragmentation by rapid gas separation in a Hawaiian fountain.Nature Geoscience,14(4).
MLA	Namiki A.,et al."Brittle fragmentation by rapid gas separation in a Hawaiian fountain".Nature Geoscience 14.4(2021).