Elastic and Anelastic Structure Beneath Eurasia.
Final rept. 1 Jul 92-30 Sep 96,
HARVARD UNIV CAMBRIDGE MA
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The primary objective of this work has been to map the variations of elastic mantle properties beneath Eurasia over horizontal length scales of approximately 1000-1500 kilometers and vertial length scales of 50-100 kilometers in the upper mantle. Large and diverse datasets of seismic waveforms, absolute and relative body wave travel times, and surface wave phase velocity and amplitudes have been collected and have been analyzed. Several tens of thousands of measurements of intermediate period surface wave dispersion have been made in order to characterize and properly account for the highly heterogeneous velocity structure associated with the crust and the uppermost mantle. Global maps of phase velocity for Love and Rayleigh waves in the period range 35-150 seconds have been produced. The new dataset of surface wave dispersion has been combined with previously collected data in the finalization of a new 3-D whole mantle model. In comparison with previous Harvard mantle models the horizontal resolution has been increased by expanding the global structure up to spherical harmonic degree l 20, and a radial parameterization has been adopted which gives better vertical resolution in the upper mantle.
- Geology, Geochemistry and Mineralogy