Walker, K.T., G. H.R. Bokelmann, S. L. Klemperer, 2001,
Shear-wave splitting to test mantle deformation models around Hawaii,
Geophysical Research Letters , 28, 22, 3219-3322
Seismic anisotropy allows us to study studying deformation in the mantle,
and it can thus help to constrain mantle flow in the vicinity of hotspots.
Hypotheses for the cause of seismic anisotropy in this environment
include the "parabolic asthenospheric flow" model: radial flow from a
mantle plume impinging on a
moving lithosphere is dragged by the plate in the direction of absolute plate motion.
In map view, this gives a parabolic pattern of flow, opening in the direction of plate motion.
We present new observations of shear-wave splitting from land and
ocean stations for the region around the Hawaiian islands which are
explained by the parabolic flow model.
The observations suggest strong anisotropy under the Hawaiian islands
which may be explained if
dislocation-creep persists to larger depths there than in other regions,
perhaps due to the higher temperatures near hotspots.
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