Down-dip variations in a subducting low-velocity zone linked to episodic tremor and slip: a new constraint from ScSp waves

Abstract Fluids are thought to play an important role in controlling episodic tremor and slow slip (ETS) in subduction zones. Therefore, constraining the along-dip distribution of fluids is necessary to better understand source mechanism of ETS, and particularly the role played by fluids in ETS gene...

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Autores principales:	Mitsuhiro Toya, Aitaro Kato, Takuto Maeda, Kazushige Obara, Tetsuya Takeda, Koshun Yamaoka
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2017
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/ab81dca3969a4dfbb8293af271068cf5
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spelling	oai:doaj.org-article:ab81dca3969a4dfbb8293af271068cf52021-12-02T11:41:22ZDown-dip variations in a subducting low-velocity zone linked to episodic tremor and slip: a new constraint from ScSp waves10.1038/s41598-017-03048-62045-2322https://doaj.org/article/ab81dca3969a4dfbb8293af271068cf52017-06-01T00:00:00Zhttps://doi.org/10.1038/s41598-017-03048-6https://doaj.org/toc/2045-2322Abstract Fluids are thought to play an important role in controlling episodic tremor and slow slip (ETS) in subduction zones. Therefore, constraining the along-dip distribution of fluids is necessary to better understand source mechanism of ETS, and particularly the role played by fluids in ETS generation. Here, we report clear observations of coherent ScSp phases with a dense seismic array in western Shikoku, Japan, where ETS has been most active over the past decade. Using numerical simulations of elastic-wave propagation to reproduce the observed ScSp phases, we demonstrate that, relative to shallower depths, either the Vp/Vs ratio or the thickness of a low-velocity zone (LVZ) within the subducting oceanic crust increases with depth beneath the mantle wedge corner where ETS has been observed. Based on these depth dependences of the structural elements, a wide semi-ductile shear zone appears to be lubricated by high-pressurized fluid in the subducting oceanic crust at ETS source depths, and to be a key factor regulating ETS activity.Mitsuhiro ToyaAitaro KatoTakuto MaedaKazushige ObaraTetsuya TakedaKoshun YamaokaNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 7, Iss 1, Pp 1-10 (2017)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Mitsuhiro Toya Aitaro Kato Takuto Maeda Kazushige Obara Tetsuya Takeda Koshun Yamaoka Down-dip variations in a subducting low-velocity zone linked to episodic tremor and slip: a new constraint from ScSp waves
description	Abstract Fluids are thought to play an important role in controlling episodic tremor and slow slip (ETS) in subduction zones. Therefore, constraining the along-dip distribution of fluids is necessary to better understand source mechanism of ETS, and particularly the role played by fluids in ETS generation. Here, we report clear observations of coherent ScSp phases with a dense seismic array in western Shikoku, Japan, where ETS has been most active over the past decade. Using numerical simulations of elastic-wave propagation to reproduce the observed ScSp phases, we demonstrate that, relative to shallower depths, either the Vp/Vs ratio or the thickness of a low-velocity zone (LVZ) within the subducting oceanic crust increases with depth beneath the mantle wedge corner where ETS has been observed. Based on these depth dependences of the structural elements, a wide semi-ductile shear zone appears to be lubricated by high-pressurized fluid in the subducting oceanic crust at ETS source depths, and to be a key factor regulating ETS activity.
format	article
author	Mitsuhiro Toya Aitaro Kato Takuto Maeda Kazushige Obara Tetsuya Takeda Koshun Yamaoka
author_facet	Mitsuhiro Toya Aitaro Kato Takuto Maeda Kazushige Obara Tetsuya Takeda Koshun Yamaoka
author_sort	Mitsuhiro Toya
title	Down-dip variations in a subducting low-velocity zone linked to episodic tremor and slip: a new constraint from ScSp waves
title_short	Down-dip variations in a subducting low-velocity zone linked to episodic tremor and slip: a new constraint from ScSp waves
title_full	Down-dip variations in a subducting low-velocity zone linked to episodic tremor and slip: a new constraint from ScSp waves
title_fullStr	Down-dip variations in a subducting low-velocity zone linked to episodic tremor and slip: a new constraint from ScSp waves
title_full_unstemmed	Down-dip variations in a subducting low-velocity zone linked to episodic tremor and slip: a new constraint from ScSp waves
title_sort	down-dip variations in a subducting low-velocity zone linked to episodic tremor and slip: a new constraint from scsp waves
publisher	Nature Portfolio
publishDate	2017
url	https://doaj.org/article/ab81dca3969a4dfbb8293af271068cf5
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Down-dip variations in a subducting low-velocity zone linked to episodic tremor and slip: a new constraint from ScSp waves

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