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The authors investigate the structural change of a ZnO–P 2 O 5 sintered matrix for the preparation of SnO-doped zinc phosphate (SZP) glass using a platinum crucible. Heat treatment of zinc oxide and ammonium phosphate at 800 °C causes the formation of a Zn 2 P 2 O 7 -like species, which is effective in preventing damage to the platinum crucible. Although the thermal property of the glass was affected by added Al 2 O 3 , Al 2 O 3 hardly affects the quantum efficiency of the SZP glass phosphor. This process is important for the fabrication of contamination-free phosphate glass using ammonium phosphate as a starting material.

We study the cumulative change of the coseismic, crustal gravitational energy caused by earthquakes occurring in two regions with active tectonics: the western USA during 1992 to 1999, and Japan during January 1997 to August 2000. We use regional earthquake source mechanism catalogues available for these regions in order to increase spatial coverage and resolution. The catalogues, however, contain very shallow earthquakes for which the conventional normal mode approach has difficulties in calculating the gravitational energy change under slow convergence in the mode summations. To overcome this problem, we employ a ‘direct’ solution approach which allows to generate very accurate kernels for the integration of the coseismic gravitational energy change. In the western USA, the Coast Ranges and the Transverse Ranges show systematically positive gravitational energy changes while the margin of the Basin and Range shows negative changes. In Japan, the northeastern part shows predominantly positive changes while the southwestern part shows negative to weak positive changes. These systematic patterns well correspond to the regional tectonic regime: gravitational energy gain for compressional tectonics and energy loss for extensional tectonics. The total (global), cumulative crustal gravitational energy change caused by the earthquakes occurring in the western USA is +6.1×10 17 J, and it is +2.7×10 17 J by the earthquakes in Japan. These energy changes are positive in both regions which indicates the predominance of the compressional stress state with respect to the earthquake occurrence.

Major element chemistry of mid-ocean ridge basalt, S-wave velocity and bathymetry along the Mid-Atlantic Ridge are correlated on an intermediate length scale, and the large anomalies in these observations are associated with hotspot locations. The best correlations are for at depths of 100–200 km, and there is no correlation for depths of 300 km or deeper. S-Wave velocities are low directly under the Mid-Atlantic Ridge above 100 km, but the low-velocity regions shift away from the ridge at greater depth, and a sinuous strip of asthenospheric low velocity extends along the Atlantic hotspots from the Azores to Tristan da Cunha. These features suggest that common physical processes in the upper mantle produce these anomalies. An inspection of the history of the Atlantic Ocean suggests that the asthenospheric low-velocity strip may record earlier ridge position or possible upwelling in the mantle. Possible interaction between hotspots and the ridge blurs the distinction between passive and active upwellings.

The most direct method for constraining physical properties of the outermost core involves analysis of SnKS waveforms (where n is an integer). However, the physical nature of this region remains ambiguous in spite of its significance in geodynamic, geomagnetic, and seismic models of the Earth's deep interior. Global inversion for P-wave velocity in the outermost 200 km of the core from SKS and SKKS waveforms is examined here. The inversion process consists of constructing synthetic seismograms using normal mode theory, and solving for first-order perturbations to P-wave velocity. Spheroidal modes with periods between 33 and 100 s are chosen to model the waveforms and P-wave velocity perturbation is solved along individual raypaths, assuming a laterally homogeneous initial model. The dataset includes about 800 digital, long-period radial seismograms from earthquakes which have occurred globally. Seismograms were chosen for source-receiver distances of 110–130° in which SKS and SKKS are best isolated in time from nearby phases. We have attempted to remove the effects of mantle heterogeneity by incorporating the mantle velocity model MDLSH. Figures of P-wave velocity results, plotted at the midpoint between source and receiver, show large-scale patterns of positive and negative lateral velocity variation. There are also regions of inconsistencies, not simply explained by core-mantle boundary (CMB) topography or crisscrossing raypaths. There is no clear dependence of residuals on latitude. Incorporation of a modified version of MDLSH does not significantly change our solutions, suggesting that the resolution length scales of global mantle models are too large to remove important smaller-wavelength (less than 1000 km) mantle heterogeneity effects. Furthermore, raypaths of SKS and SKKS independently go through laterally different structure relative to normal mode wavelengths, starting well above the CMB. These results suggest that simultaneous waveform inversion for P- and S-wave velocities is a more reliable way of constructing a model of outermost core structure.

Global Love wave phase velocity variation was constructed for periods between 80 and 200 s by using approximately 9000 paths from 971 earthquakes (with M ≥ 5.5). The data set was from GDSN and GEOSCOPE networks between 1980 and 1987. We examined both the spherical harmonic expansion method and the block parameterization method. With a simple, constant damping parameter approach, synthetic tests showed that more accurate results were obtained by the block parameterization method than by the spherical harmonic expansion method. We adopted the block inversion method with a (nearly) equal area block (5° × 5° near the equator) discretization. The general pattern of the resulting maps were consistent with previous global and local studies. With a discretization of 5° by 5°, the maps were detailed enough to test some plate tectonic models. For the Pacific, Atlantic and Indian Oceans, surface-wave velocities increased smoothly to plate ages older than 100 Ma. Simple forward modeling showed that seismic phase velocity variation with a continuous thickening of lithosphere up to about 150 Ma fits the present observation, disagreeing with the model deduced from the heat flow and ocean depth data, which change variations at about 60–80 Ma. The seismic phase velocity variations in different oceans showed systematic differences at younger ages, and convergence beyond 100 Ma. The difference at younger ages implies a failure of scaling derived from a simple thermal boundary layer model for oceanic plates. Age-seismic phase velocity relationships on each side of ridges were also examined and asymmetric velocity variations were found, which suggests differences in thermal states from one side of the ridge to the other. In order to further examine the thermal state of the lithosphere, average age-phase velocity relations were established for each ocean, and subtracted from phase velocity variation maps. The results indicated broad, low-velocity regions in the south Pacific (super-swell region), the south and west Indian Ocean, and high-velocity regions east of the East Pacific Rise and in the north to northeast Indian Ocean. The results reflect the asymmetry of phase velocity variation about ridges. There is some correlation between hot-spot locations and low-velocity anomalies, but additional, large-scale thermal anomalies exist under old oceanic plate.