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High-resolution seismic tomographic models of the upper mantle provide powerful new constraints on theories of plate tectonics and hotspots. Midocean ridges have extremely low seismic velocities to a depth of 100 kilometers. These low velocities imply partial melting. At greater depths, low-velocity and high-velocity anomalies record, respectively, previous(More)
reliable local ‘standards of rest’ — standards of precisely known and completely stable wavelengths. Until now, discharge lamps and absorption spectra have served well. The first technique provides stabilized, reasonably welldistributed emission lines for elements such as thorium and argon (Fig. 1b); the second works by passing starlight through a cell(More)
The authors report on the correlation between the photoluminescence (PL) property and the SnO amount in SnO-ZnO-P2O5 (SZP) glass. In the PL excitation (PLE) spectra of the SZP glass containing Sn2+ emission center, two S1 states, one of which is strongly affected by SnO amount, are assumed to exist. The PLE band closely correlates with the optical band edge(More)
Three-dimensional imaging of the Earth's interior, called seismic tomography, has achieved breakthrough advances in the last two decades, revealing fundamental geodynamical processes throughout the Earth's mantle and core. Convective circulation of the entire mantle is taking place, with subducted oceanic lithosphere sinking into the lower mantle,(More)
We calculated SKS splitting parameters for the California Integrated Seismic Network. In southern California, we also estimated splitting in the upper 100 km using azimuthal anisotropy determined from surface waves. The inferred splitting from surface waves in the mantle lithosphere is small (on average <0.2 sec) compared with SKS splitting (1.5 sec) and(More)
This paper investigates the utility of computing Time-Domain Green's Functions (TDGF) to be used for estimating velocity and attenuation structure for the purposes of nuclear explosion monitoring over local and near-regional distances. Our objective is to extend and apply the methodology of deriving TDGF for propagation between two receivers by cross(More)
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