D″ anisotropy beneath Southeast Asia

C Thomas; J Wookey; M Simpson

doi:10.1029/2006GL028965

D″ anisotropy beneath Southeast Asia

C Thomas, J Wookey, M Simpson

School of Earth Sciences

Research output: Contribution to journal › Article (Academic Journal)

21 Citations (Scopus)

Abstract

Earthquakes from the Banda Sea and Flores Sea region recorded at the Kyrgyz Network in the Tien Shan region show evidence for anisotropy in the lowermost mantle beneath South East Asia. Shear-wave splitting is measured for the ScS phase after a receiver-side correction is applied. Individual results show scatter in measured time lag and fast direction, but stacking these gives a stable estimate of 0.8 ± 0.04 s and 43 ± 4 degrees. This equates to a fast-shear wave with a polarisation deviation from horizontal (at the bounce point) of around 9 degrees. The simplest model to explain is a transversely isotropic medium with a slight dip to the east, and an inferred anisotropy of ∼0.25%. This is compatible with previous observations of VSH > VSV for this region. Scenarios which might explain the observed anisotropy include sheared melt pockets or aligned post-perovskite crystals associated with palaeosubduction of the Pacific plate and Indian plate.

Original language	English
Pages (from-to)	1 - 6
Number of pages	6
Journal	Geophysical Research Letters
Volume	34 (4) (L04301)
DOIs	https://doi.org/10.1029/2006GL028965
Publication status	Published - Feb 2007

Bibliographical note

Publisher: American Geophysical Union

Access to Document

10.1029/2006GL028965

http://www.agu.org/pubs/crossref/2007/2006GL028965.shtml

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Projects

1 Finished

AN INTEGRATED SEISMOLOGICAL STUDY OF THE HETEROGENITY AND ANGIOTROPY OF THE LOWERMOST MANTLE

Wookey, J. M.

1/11/05 → 1/11/08

Project: Research

Activities

1 - Research and Teaching at External Organisation

Collaboration with Prof. Dr. Christine Thomas

James M Wookey (Contributor)

2005 → …

Activity: Other activity types › - Research and Teaching at External Organisation

Cite this

Thomas, C., Wookey, J., & Simpson, M. (2007). D″ anisotropy beneath Southeast Asia. Geophysical Research Letters, 34 (4) (L04301), 1 - 6. https://doi.org/10.1029/2006GL028965

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abstract = "Earthquakes from the Banda Sea and Flores Sea region recorded at the Kyrgyz Network in the Tien Shan region show evidence for anisotropy in the lowermost mantle beneath South East Asia. Shear-wave splitting is measured for the ScS phase after a receiver-side correction is applied. Individual results show scatter in measured time lag and fast direction, but stacking these gives a stable estimate of 0.8 ± 0.04 s and 43 ± 4 degrees. This equates to a fast-shear wave with a polarisation deviation from horizontal (at the bounce point) of around 9 degrees. The simplest model to explain is a transversely isotropic medium with a slight dip to the east, and an inferred anisotropy of ∼0.25%. This is compatible with previous observations of VSH > VSV for this region. Scenarios which might explain the observed anisotropy include sheared melt pockets or aligned post-perovskite crystals associated with palaeosubduction of the Pacific plate and Indian plate.",

author = "C Thomas and J Wookey and M Simpson",

note = "Publisher: American Geophysical Union",

year = "2007",

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doi = "10.1029/2006GL028965",

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AU - Wookey, J

AU - Simpson, M

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N2 - Earthquakes from the Banda Sea and Flores Sea region recorded at the Kyrgyz Network in the Tien Shan region show evidence for anisotropy in the lowermost mantle beneath South East Asia. Shear-wave splitting is measured for the ScS phase after a receiver-side correction is applied. Individual results show scatter in measured time lag and fast direction, but stacking these gives a stable estimate of 0.8 ± 0.04 s and 43 ± 4 degrees. This equates to a fast-shear wave with a polarisation deviation from horizontal (at the bounce point) of around 9 degrees. The simplest model to explain is a transversely isotropic medium with a slight dip to the east, and an inferred anisotropy of ∼0.25%. This is compatible with previous observations of VSH > VSV for this region. Scenarios which might explain the observed anisotropy include sheared melt pockets or aligned post-perovskite crystals associated with palaeosubduction of the Pacific plate and Indian plate.

AB - Earthquakes from the Banda Sea and Flores Sea region recorded at the Kyrgyz Network in the Tien Shan region show evidence for anisotropy in the lowermost mantle beneath South East Asia. Shear-wave splitting is measured for the ScS phase after a receiver-side correction is applied. Individual results show scatter in measured time lag and fast direction, but stacking these gives a stable estimate of 0.8 ± 0.04 s and 43 ± 4 degrees. This equates to a fast-shear wave with a polarisation deviation from horizontal (at the bounce point) of around 9 degrees. The simplest model to explain is a transversely isotropic medium with a slight dip to the east, and an inferred anisotropy of ∼0.25%. This is compatible with previous observations of VSH > VSV for this region. Scenarios which might explain the observed anisotropy include sheared melt pockets or aligned post-perovskite crystals associated with palaeosubduction of the Pacific plate and Indian plate.

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DO - 10.1029/2006GL028965

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JO - Geophysical Research Letters

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