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Trench-parallel flow and seismic anisotropy in the Mariana and Andean subduction systems.
- Source :
-
Nature . 12/14/2007, Vol. 450 Issue 7173, p1222-1225. 4p. 4 Graphs. - Publication Year :
- 2007
-
Abstract
- Shear-wave splitting measurements above the mantle wedge of the Mariana and southern Andean subduction zones show trench-parallel seismically fast directions close to the trench and abrupt rotations to trench-perpendicular anisotropy in the back arc. These patterns of seismic anisotropy may be caused by three-dimensional flow associated with along-strike variations in slab geometry. The Mariana and Andean subduction systems are associated with the largest along-strike variations of slab geometry observed on Earth and are ideal for testing the link between slab geometry and solid-state creep processes in the mantle. Here we show, with fully three-dimensional non-newtonian subduction zone models, that the strong curvature of the Mariana slab and the transition to shallow slab dip in the Southern Andes give rise to strong trench-parallel stretching in the warm-arc and warm-back-arc mantle and to abrupt rotations in stretching directions that are accompanied by strong trench-parallel stretching. These models show that the patterns of shear-wave splitting observed in the Mariana and southern Andean systems may be caused by significant three-dimensional flow induced by along-strike variations in slab geometry. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00280836
- Volume :
- 450
- Issue :
- 7173
- Database :
- Academic Search Index
- Journal :
- Nature
- Publication Type :
- Academic Journal
- Accession number :
- 27997270
- Full Text :
- https://doi.org/10.1038/nature06429