Episodicity of seismicity accompanying melt intrusion into the crust

White, R. S. and Redfern, S. A. T. and Chien, S-Y (2012) Episodicity of seismicity accompanying melt intrusion into the crust. Geophysical Research Letters, 39. L08306. DOI https://doi.org/10.1029/2012GL051392

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Abstract

Microseismicity from a dike intruding the mid-crust of Iceland occurs episodically on fractures orientated parallel to the dike plane. We interpret it as caused by fragments of chilled magma being broken and pushed along the conduit by melt flow. Laboratory experiments on basalt samples under shear strains of 104 show that the shear strength of a sample cooled through the glass transition initially increases to a maximum at 0.7 homologous temperature, but subsequently decreases until failure at 0.58 homologous temperature. We interpret the failure as due to the connection of microcracks. Episodicity in microseismicity on timescales of hours to days can arise from a cycle in which magma in 0.1–0.5 meter thick dikes first cools and becomes stronger, but then weakens along the dike margins with continued cooling against the country rock. Continued pressure of magma from below may then cause failure along dikeparallel fractures.

Item Type:	Article
Additional Information:	Romeo Green: http://www.sherpa.ac.uk/romeo/issn/0094-8276/
Uncontrolled Keywords:	2012AREP; IA63;
Subjects:	02 - Geodynamics, Geophysics and Tectonics
Divisions:	02 - Geodynamics, Geophysics and Tectonics 08 - Green Open Access 10 - Explosive Earth
Journal or Publication Title:	Geophysical Research Letters
Volume:	39
Page Range:	L08306
Identification Number:	https://doi.org/10.1029/2012GL051392
Depositing User:	Sarah Humbert
Date Deposited:	15 Mar 2012 09:02
Last Modified:	22 Jun 2016 17:15
URI:	http://eprints.esc.cam.ac.uk/id/eprint/2406

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