Physics
Scientific paper
Sep 2004
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004pepi..146..469h&link_type=abstract
Physics of the Earth and Planetary Interiors, Volume 146, Issue 3-4, p. 469-481.
Physics
13
Anisotropy, D'', Seismology, Core Phases, Composition Of The Earth
Scientific paper
Anisotropy in the lowermost few 100 km of mantle, or D'' region, is indicative of deformation-induced alignment of crystals and/or inclusions of material, and as such offers insights into the dynamic nature of this region. Observations of shear-wave splitting in phases that transit this region provide constraints on such anisotropy. We investigate the effects of lower-mantle seismic anisotropy on SKS and SKKS phases through linked effective-medium modelling and ray-based waveform modelling. A mantle with vertical-transverse-isotropy (VTI) will not produce any splitting in such core phases. Instead we consider the effects of azimuthal-anisotropy due to aligned disk-shaped and tubular inclusions and aligned perovskite, periclase and columbite. Models are constructed subject to constraints imposed by observed anisotropy (<3%) and plausible variations in aggregate isotropic velocities (<+/- 2.5%). Melt-filled inclusions are much more effective in generating anisotropy than solid-filled inclusions and disk-shaped inclusions produce more anisotropy than tubular inclusions. In general the degree of splitting produced by most of the models is small, similar to that produced by the crust (<0.5s). The exceptions are melt-filled vertically-aligned disk-shaped inclusions and horizontally aligned periclase, the former most likely in low-velocity regions, the latter in high-velocity regions. Both models produce splitting significant enough to mask the effects of upper-mantle anisotropy. Strong azimuthal variations in splitting and discrepancies in SKS and SKKS splitting are diagnostic of these anisotropic models.
Hall Stéphen A.
Kendall J.-Michael
van der Baan Mirko
No associations
LandOfFree
Some comments on the effects of lower-mantle anisotropy on SKS and SKKS phases does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Some comments on the effects of lower-mantle anisotropy on SKS and SKKS phases, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Some comments on the effects of lower-mantle anisotropy on SKS and SKKS phases will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-802669