Anisotropy in the subducting slab: Observations from Philippine Sea plate events in Taiwan

Kate Huihsuan Chen; Yu Lung Tseng; Takashi Furumura; Brian L.N. Kennett

doi:10.1002/2015GL066227

Anisotropy in the subducting slab: Observations from Philippine Sea plate events in Taiwan

Kate Huihsuan Chen^*, Yu Lung Tseng, Takashi Furumura, Brian L.N. Kennett

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

6 Citations (Scopus)

Abstract

In the southernmost Ryukyu subduction zone, slab-guiding behavior from intermediate-depth earthquakes is well documented with a low-frequency (<2 Hz) first P arrival followed by sustained high-frequency (3-10 Hz) wave trains. Such waves developed by propagating along a long path within the slab are expected to have high sensitivity to anisotropy within the slab. We determine shear wave splitting parameters from 178 intraplate events that are deeper than 100 km. The possible slab-anisotropy-associated polarization pattern shows the fast direction at N65°E and delay time of 0.13-0.45 s. This is stronger than the previously documented crust effect (<0.1 s), similar to the mantle wedge effect (0.28 s in average), but weaker than the upper mantle effect (1.3 s in average) in Taiwan. The fast axis reflects the fossil spreading direction of Philippine Sea plate with minor clockwise rotation due to the collision to Eurasian plate.

Original language	English
Pages (from-to)	10248-10255
Number of pages	8
Journal	Geophysical Research Letters
Volume	42
Issue number	23
DOIs	https://doi.org/10.1002/2015GL066227
Publication status	Published - 16 Dec 2015

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title = "Anisotropy in the subducting slab: Observations from Philippine Sea plate events in Taiwan",

abstract = "In the southernmost Ryukyu subduction zone, slab-guiding behavior from intermediate-depth earthquakes is well documented with a low-frequency (<2 Hz) first P arrival followed by sustained high-frequency (3-10 Hz) wave trains. Such waves developed by propagating along a long path within the slab are expected to have high sensitivity to anisotropy within the slab. We determine shear wave splitting parameters from 178 intraplate events that are deeper than 100 km. The possible slab-anisotropy-associated polarization pattern shows the fast direction at N65°E and delay time of 0.13-0.45 s. This is stronger than the previously documented crust effect (<0.1 s), similar to the mantle wedge effect (0.28 s in average), but weaker than the upper mantle effect (1.3 s in average) in Taiwan. The fast axis reflects the fossil spreading direction of Philippine Sea plate with minor clockwise rotation due to the collision to Eurasian plate.",

keywords = "Philippine Sea plate, shear wave splitting, slab anisotropy",

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T1 - Anisotropy in the subducting slab

T2 - Observations from Philippine Sea plate events in Taiwan

AU - Chen, Kate Huihsuan

AU - Tseng, Yu Lung

AU - Furumura, Takashi

AU - Kennett, Brian L.N.

PY - 2015/12/16

Y1 - 2015/12/16

N2 - In the southernmost Ryukyu subduction zone, slab-guiding behavior from intermediate-depth earthquakes is well documented with a low-frequency (<2 Hz) first P arrival followed by sustained high-frequency (3-10 Hz) wave trains. Such waves developed by propagating along a long path within the slab are expected to have high sensitivity to anisotropy within the slab. We determine shear wave splitting parameters from 178 intraplate events that are deeper than 100 km. The possible slab-anisotropy-associated polarization pattern shows the fast direction at N65°E and delay time of 0.13-0.45 s. This is stronger than the previously documented crust effect (<0.1 s), similar to the mantle wedge effect (0.28 s in average), but weaker than the upper mantle effect (1.3 s in average) in Taiwan. The fast axis reflects the fossil spreading direction of Philippine Sea plate with minor clockwise rotation due to the collision to Eurasian plate.

AB - In the southernmost Ryukyu subduction zone, slab-guiding behavior from intermediate-depth earthquakes is well documented with a low-frequency (<2 Hz) first P arrival followed by sustained high-frequency (3-10 Hz) wave trains. Such waves developed by propagating along a long path within the slab are expected to have high sensitivity to anisotropy within the slab. We determine shear wave splitting parameters from 178 intraplate events that are deeper than 100 km. The possible slab-anisotropy-associated polarization pattern shows the fast direction at N65°E and delay time of 0.13-0.45 s. This is stronger than the previously documented crust effect (<0.1 s), similar to the mantle wedge effect (0.28 s in average), but weaker than the upper mantle effect (1.3 s in average) in Taiwan. The fast axis reflects the fossil spreading direction of Philippine Sea plate with minor clockwise rotation due to the collision to Eurasian plate.

KW - Philippine Sea plate

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KW - slab anisotropy

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U2 - 10.1002/2015GL066227

DO - 10.1002/2015GL066227

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JO - Geophysical Research Letters

JF - Geophysical Research Letters

IS - 23

ER -

Anisotropy in the subducting slab: Observations from Philippine Sea plate events in Taiwan

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