| 研究実績の概要 |
P- and S-wave elastic velocities are unique tools we have to explore the chemical composition and structures of the inaccessible deep Earth, by comparing high pressure mineral physics data with seismological observations. In this research project, we proposed to elucidate locally the seismicity of regions of stagnating slabs, independently from global models, on the basis of laboratory sound velocity measurements, geological record of the slab and local seismological observations.
In this FY, we further developed ultrasonic interferometry and synchrotron X-ray techniques in the multi-anvil press at the beamline BL04B1 in SPring-8, allowing experiments at the pressures and temperatures of the uppermost lower mantle (exp. at P~ 25-31 GPa and T up to 2100 K). The improved techniques were applied to investigate the sound velocities of Mid-Ocean Ridge Basalt (MORB) and harzburgite rock aggregates accordingly to the original plan, but also to the Al-rich Fe-bearing Bridgmanite, the major mineral of the Earth's lower mantle. The elastic wave velocity models derived from our study, are readily available for comparison with global seismic models while methods to compare with local seismic models by waveform inversion methods are still underway.
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