地震波傳遞和全球走時層析成像：香蕉－甜甜圈理論(II)
Date Issued
2003
Date
2003
Author(s)
DOI
912119M002027
Abstract
We present the global distribution of shear velocity heterogeneity in the lowermost
500 km of the mantle derived from a joint inversion of differential S (or diffracted S)-SKS and
ScS-S travel-time residuals measured by long-period waveforms dominant at 25 s. Fréchet or
banana-doughnut kernel theory is utilized to forward modeling of finite-frequency travel-time
measurements. A model parameterization based on a multiresolution wavelet representation is
implemented to inversely solve for spatial variations in mantle shear wavespeed perturbations.
The resolved velocity heterogeneity strength is about twice as much as that in the previous model 3
constrained by similar dataset but ray-obtained tomography. Surface hotspots in the Central
Pacific and the Indian-Africa are correlated with deep-rooted mantle plumes located within or on
the edge of broad, low-velocity D" regions. Relatively fast velocity structures that underlie
beneath the Circum-Pacific Rim are associated with ancient cold subducted materials.
Subjects
finite-frequency traveltime tomography
shear velocity heterogeneity
core-mantle
boundary
boundary
D” layer
multiscale model parameterization
Publisher
臺北市：國立臺灣大學地質科學系暨研究所
Type
report
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