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Detailed Reference Information |
Chen, W. and Brudzinski, M.R. (2003). Seismic anisotropy in the mantle transition zone beneath Fiji-Tonga. Geophysical Research Letters 30: doi: 10.1029/2002GL016330. issn: 0094-8276. |
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We demonstrate a rare, unequivocal case of anisotropy in the transition zone (TZ), evident from many horizontal-polarized shear-waves (SH) that arrive up to 3 s earlier than vertical-polarized shear-waves (SV). The anisotropic region correlates with deep earthquakes away from the active subduction zone and known boundaries of lateral heterogeneities in compression- and shear-wave speeds. We interpret the anisotropy as strong fabric associated with a large petrologic anomaly in the core of remnant lithosphere which is buoyant and stagnates in the TZ. Fast subduction of cold slab actually favors such a configuration, so slab penetration into the lower mantle does not uniformly occur. |
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Abstract |
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Keywords
Seismology, Body wave propagation, Mineralogy and Petrology, General or miscellaneous, Seismology, Core and mantle, Tectonophysics, Dynamics of lithosphere and mantle--general, Tectonophysics, Earth's interior--composition and state |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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