0033–4553:98:040463–13 $ 1.500.20:0 Anisotropy and Flow in Pacific Subduction Zone Back-arcs
Abstract—We have obtained constraints on the strength and orientation of anisotropy in the mantle beneath the Tonga, southern Kuril, Japan, and Izu-Bonin subduction zones using shear-wave splitting in S phases from local earthquakes and in teleseismic core phases such as SKS. The observed splitting...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.491.9974 2023-05-15T18:09:14+02:00 0033–4553:98:040463–13 $ 1.500.20:0 Anisotropy and Flow in Pacific Subduction Zone Back-arcs Karen M. Fischer Matthew J. Fouch Douglas A. Wiens Margaret S. Boettcher The Pennsylvania State University CiteSeerX Archives application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.491.9974 http://www.whoi.edu/cms/files/mboettcher/2004/9/Fischer+98_507.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.491.9974 http://www.whoi.edu/cms/files/mboettcher/2004/9/Fischer+98_507.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://www.whoi.edu/cms/files/mboettcher/2004/9/Fischer+98_507.pdf Key words Anisotropy text ftciteseerx 2016-08-14T00:04:06Z Abstract—We have obtained constraints on the strength and orientation of anisotropy in the mantle beneath the Tonga, southern Kuril, Japan, and Izu-Bonin subduction zones using shear-wave splitting in S phases from local earthquakes and in teleseismic core phases such as SKS. The observed splitting in all four subduction zones is consistent with a model in which the lower transition zone (520–660 km) and lower mantle are isotropic, and in which significant anisotropy occurs in the back-arc upper mantle. The upper transition zone (410–520 km) beneath the southern Kurils appears to contain weak anisotropy. The observed fast directions indicate that the geometry of back-arc strain in the upper mantle varies systematically across the western Pacific rim. Beneath Izu-Bonin and Tonga, fast directions are aligned with the azimuth of subducting Pacific plate motion and are parallel or sub-parallel to overriding plate extension. However, fast directions beneath the Japan Sea, western Honshu, and Sakhalin Island are highly oblique to subducting plate motion and parallel to present or past overriding plate shearing. Models of back-arc mantle flow that are driven by viscous coupling to local plate motions can reproduce the splitting observed in Tonga and Izu-Bonin, but further three-dimensional flow modeling is required to ascertain whether viscous plate coupling can explain the splitting observed in the southern Kurils and Japan. The fast directions in the southern Kurils and Japan may require strain in the back-arc mantle that is driven by regional or global patterns of mantle flow. Text Sakhalin Unknown Pacific Tonga ENVELOPE(7.990,7.990,63.065,63.065) |
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ftciteseerx |
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English |
topic |
Key words Anisotropy |
spellingShingle |
Key words Anisotropy Karen M. Fischer Matthew J. Fouch Douglas A. Wiens Margaret S. Boettcher 0033–4553:98:040463–13 $ 1.500.20:0 Anisotropy and Flow in Pacific Subduction Zone Back-arcs |
topic_facet |
Key words Anisotropy |
description |
Abstract—We have obtained constraints on the strength and orientation of anisotropy in the mantle beneath the Tonga, southern Kuril, Japan, and Izu-Bonin subduction zones using shear-wave splitting in S phases from local earthquakes and in teleseismic core phases such as SKS. The observed splitting in all four subduction zones is consistent with a model in which the lower transition zone (520–660 km) and lower mantle are isotropic, and in which significant anisotropy occurs in the back-arc upper mantle. The upper transition zone (410–520 km) beneath the southern Kurils appears to contain weak anisotropy. The observed fast directions indicate that the geometry of back-arc strain in the upper mantle varies systematically across the western Pacific rim. Beneath Izu-Bonin and Tonga, fast directions are aligned with the azimuth of subducting Pacific plate motion and are parallel or sub-parallel to overriding plate extension. However, fast directions beneath the Japan Sea, western Honshu, and Sakhalin Island are highly oblique to subducting plate motion and parallel to present or past overriding plate shearing. Models of back-arc mantle flow that are driven by viscous coupling to local plate motions can reproduce the splitting observed in Tonga and Izu-Bonin, but further three-dimensional flow modeling is required to ascertain whether viscous plate coupling can explain the splitting observed in the southern Kurils and Japan. The fast directions in the southern Kurils and Japan may require strain in the back-arc mantle that is driven by regional or global patterns of mantle flow. |
author2 |
The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
Karen M. Fischer Matthew J. Fouch Douglas A. Wiens Margaret S. Boettcher |
author_facet |
Karen M. Fischer Matthew J. Fouch Douglas A. Wiens Margaret S. Boettcher |
author_sort |
Karen M. Fischer |
title |
0033–4553:98:040463–13 $ 1.500.20:0 Anisotropy and Flow in Pacific Subduction Zone Back-arcs |
title_short |
0033–4553:98:040463–13 $ 1.500.20:0 Anisotropy and Flow in Pacific Subduction Zone Back-arcs |
title_full |
0033–4553:98:040463–13 $ 1.500.20:0 Anisotropy and Flow in Pacific Subduction Zone Back-arcs |
title_fullStr |
0033–4553:98:040463–13 $ 1.500.20:0 Anisotropy and Flow in Pacific Subduction Zone Back-arcs |
title_full_unstemmed |
0033–4553:98:040463–13 $ 1.500.20:0 Anisotropy and Flow in Pacific Subduction Zone Back-arcs |
title_sort |
0033–4553:98:040463–13 $ 1.500.20:0 anisotropy and flow in pacific subduction zone back-arcs |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.491.9974 http://www.whoi.edu/cms/files/mboettcher/2004/9/Fischer+98_507.pdf |
long_lat |
ENVELOPE(7.990,7.990,63.065,63.065) |
geographic |
Pacific Tonga |
geographic_facet |
Pacific Tonga |
genre |
Sakhalin |
genre_facet |
Sakhalin |
op_source |
http://www.whoi.edu/cms/files/mboettcher/2004/9/Fischer+98_507.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.491.9974 http://www.whoi.edu/cms/files/mboettcher/2004/9/Fischer+98_507.pdf |
op_rights |
Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
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1766181701779718144 |