气候变化领域集成服务门户(CCPortal): The Effects of Degassing on Magmatic Gas Waves and Long Period Eruptive Precursors at Silicic Volcanoes

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DOI	10.1029/2020JB019755
	The Effects of Degassing on Magmatic Gas Waves and Long Period Eruptive Precursors at Silicic Volcanoes
	Jordan J.S.; Bercovici D.; Liao Y.; Michaut C.
发表日期	2020
ISSN	21699313
卷号	125 期号:10
英文摘要	Cyclical ground deformation, associated seismicity, and elevated degassing are important precursors to explosive eruptions at silicic volcanoes. Regular intervals for elevated activity (6–30 hr) have been observed at volcanoes such as Mount Pinatubo in the Philippines and Soufrière Hills in Montserrat. Here, we explore a hypothesis originally proposed by Michaut et al. (2013, https://doi.org/10.1038/ngeo1928) where porosity waves containing magmatic gas are responsible for the observed periodic behavior. We use two-phase theory to construct a model where volatile-rich, bubbly, viscous magma rises and decompresses. We conduct numerical experiments where magma gas waves with various frequencies are imposed at the base of the model volcanic conduit. We numerically verify the results of Michaut et al. (2013, https://doi.org/10.1038/ngeo1928) and then expand on the model by allowing magma viscosity to vary as a function of dissolved water and crystal content. Numerical experiments show that gas exsolution tends to damp the growth of porosity waves during decompression. The instability and resultant growth or decay of gas wave amplitude depends strongly on the gas density gradient and the ratio of the characteristic magma extraction rate to the characteristic magma degassing rate (Damköhler number, Da). We find that slow degassing can lead to a previously unrecognized filtering effect, where low-frequency gas waves may grow in amplitude. These waves may set the periodicity of the eruptive precursors, such as those observed at Soufrière Hills Volcano. We demonstrate that degassed, crystal-rich magma is susceptible to the growth of gas waves which may result in the periodic behavior. ©2020. American Geophysical Union. All Rights Reserved.
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187559
作者单位	Department of Earth & Planetary Sciences, Yale University, New Haven, CT, United States; Department of Earth, Environmental & Planetary Sciences, Rice University, Houston, TX, United States; Woods Hole Oceanographic Institution, Falmouth, MA, United States; Laboratoire de Géologie de Lyon, Ecole Normale Supérieure de Lyon, Université de Lyon, Paris, France; Institut Universitaire de France (IUF), Paris, France
推荐引用方式 GB/T 7714	Jordan J.S.,Bercovici D.,Liao Y.,et al. The Effects of Degassing on Magmatic Gas Waves and Long Period Eruptive Precursors at Silicic Volcanoes[J],2020,125(10).
APA	Jordan J.S.,Bercovici D.,Liao Y.,&Michaut C..(2020).The Effects of Degassing on Magmatic Gas Waves and Long Period Eruptive Precursors at Silicic Volcanoes.Journal of Geophysical Research: Solid Earth,125(10).
MLA	Jordan J.S.,et al."The Effects of Degassing on Magmatic Gas Waves and Long Period Eruptive Precursors at Silicic Volcanoes".Journal of Geophysical Research: Solid Earth 125.10(2020).