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DOI	10.1016/j.earscirev.2019.03.010
	Degassing behaviour at basaltic volcanoes: New insights from experimental investigations of different conduit geometry and magma viscosity
	Spina L.; Cannata A.; Morgavi D.; Perugini D.
发表日期	2019
ISSN	00128252
起始页码	317
结束页码	336
卷号	192
英文摘要	Understanding gas-magma dynamics in volcanic conduits and linking them with the associated geophysical signals at the surface is of fundamental importance in monitoring active volcanoes. In the past, a significant number of studies have been devoted to this topic, addressing the onset, the key factors governing each degassing regime and the related markers at the surface, particularly at basaltic volcanoes. Here, we first review such a broad and increasing literature, focusing on the main approaches used in the attempt of deciphering conduit dynamics by indirect observations: 1) analogue laboratory experiments; and 2) seismo-acoustic measurements. Then, we combine the two techniques into a novel set of experiments, addressing a crucial, yet unexplored, issue: the irregularity (i.e. the departure from an ideal smooth cylindrical shape) of the conduit surface. We built a set of epoxy conduits with various fractal dimensions (D c ; i.e. irregularity) of the internal surface, using silicone oil as a proxy for magma. Different degassing patterns (bubbly, slug and churn-annular flow) were reproduced by changing systematically: 1) injected gas flux (5 to 180 × 10 −3 l/s); 2) analogue magma viscosity (10 to 1000 Pas); 3) fractal dimension (D c ) of the conduit surface (i.e. D c = 2, D c = 2.18 and D c = 2.99). The experiments were monitored by means of a video-camera and a set of sensor aimed to detect the seismic and acoustic signals. Results show that viscosity strongly influences the transition among degassing patterns and the recurrence rate of slug bursts at the surface. Moreover, we observed an increase of the exponent of the power law equation linking squared seismic amplitude to gas flow rate with conduit roughness; the opposite trend was noticed with increasing liquid viscosity. These results have important implications for linking seismic tremor to eruption source parameters such as the volume discharge rate at different volcanoes or for investigating its temporal evolution at a single vent. © 2019 Elsevier B.V.
关键词	Conduit geometry Degassing pattern Fractal Seismo-acoustic signals Slug
英文关键词	basalt; degassing; experimental study; fractal analysis; geometry; magma; viscosity
语种	英语
来源期刊	Earth Science Reviews
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/203559
作者单位	Department of Physics and Geology, University of Perugia, Piazza Università 1, Perugia, 06100, Italy; Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Roma1, Via Di Vigna Murata 605, Rome, 00143, Italy; Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo, Sezione di Catania, Piazza Roma, Catania, 95100, Italy; Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Università di Catania, Corso Italia 55, Catania, 95100, Italy
推荐引用方式 GB/T 7714	Spina L.,Cannata A.,Morgavi D.,et al. Degassing behaviour at basaltic volcanoes: New insights from experimental investigations of different conduit geometry and magma viscosity[J],2019,192.
APA	Spina L.,Cannata A.,Morgavi D.,&Perugini D..(2019).Degassing behaviour at basaltic volcanoes: New insights from experimental investigations of different conduit geometry and magma viscosity.Earth Science Reviews,192.
MLA	Spina L.,et al."Degassing behaviour at basaltic volcanoes: New insights from experimental investigations of different conduit geometry and magma viscosity".Earth Science Reviews 192(2019).