气候变化领域集成服务门户(CCPortal): Glaciohydraulic seismic tremors on an Alpine glacier

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DOI	10.5194/tc-14-287-2020
	Glaciohydraulic seismic tremors on an Alpine glacier
	Lindner F.; Walter F.; Laske G.; Gimbert F.
发表日期	2020
ISSN	19940416
起始页码	287
结束页码	308
卷号	14 期号:1
英文摘要	Hydraulic processes impact viscous and brittle ice deformation. Water-driven fracturing as well as turbulent water flow within and beneath glaciers radiate seismic waves which provide insights into otherwise hard-to-access englacial and subglacial environments. In this study, we analyze glaciohydraulic tremors recorded by four seismic arrays installed in different parts of Glacier de la Plaine Morte, Switzerland. Data were recorded during the 2016 melt season including the sudden subglacial drainage of an ice-marginal lake. Together with our seismic data, discharge, lake level, and ice flow measurements provide constraints on glacier hydraulics. We find that the tremors are generated by subglacial water flow, in moulins, and by icequake bursts. The dominating process can vary on sub-kilometer and sub-daily scales. Consistent with field observations, continuous source tracking via matched-field processing suggests a gradual up-glacier progression of an efficient drainage system as the melt season progresses. The ice-marginal lake likely connects to this drainage system via hydrofracturing, which is indicated by sustained icequake signals emitted from the proximity of the lake basin and starting roughly 24 h prior to the lake drainage. To estimate the hydraulics associated with the drainage, we use tremor-discharge scaling relationships. Our analysis suggests a pressurization of the subglacial environment at the drainage onset, followed by an increase in the hydraulic radii of the conduits and a subsequent decrease in the subglacial water pressure as the capacity of the drainage system increases. The pressurization is in phase with the drop in the lake level, and its retrieved maximum coincides with ice uplift measured via GPS. Our results highlight the use of cryo-seismology for monitoring glacier hydraulics. © 2020. This work is distributed under the Creative Commons Attribution 4.0 License.
英文关键词	brittle deformation; drainage; glacioisostasy; ice-dammed lake; lake level; melt; microtremor; seismic wave; subglacial environment; valley glacier; water flow; Bern [Switzerland]; Plaine Morte Glacier; Switzerland
语种	英语
来源期刊	Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/202146
作者单位	Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zürich, Zürich, Switzerland; Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, UC San Diego, San diego, United States; Institut des Géosciences de l'Environnement, Université Grenoble Alpes, UMR CNRS 5001, Grenoble, France
推荐引用方式 GB/T 7714	Lindner F.,Walter F.,Laske G.,et al. Glaciohydraulic seismic tremors on an Alpine glacier[J],2020,14(1).
APA	Lindner F.,Walter F.,Laske G.,&Gimbert F..(2020).Glaciohydraulic seismic tremors on an Alpine glacier.Cryosphere,14(1).
MLA	Lindner F.,et al."Glaciohydraulic seismic tremors on an Alpine glacier".Cryosphere 14.1(2020).