Seismic Structure of the Transition Zone Associated with the Japanese Subduction Zones

小行星9526678 这项研究是调查上地幔过渡带的地震结构，从400到700公里的深度，这是了解地球地幔内的对流模式以及地球的化学成分的关键。 在本项目中，计划利用上地幔（在区域台站记录的三重P和S波形）描绘与日本俯冲带有关的过渡带的地震结构。 本文讨论了目前存在的三个主要问题：（1）过渡带俯冲带的速度异常是什么;（2）俯冲板片是在过渡带底部变平还是延伸到下地幔;以及3）上地幔的地震结构是否支持化学分层模型或温度不连续模型-相关相变大约在410 km处，并且可能在大约525 km处。 *** ??

9526678 Tajima This research is to investigate the seismic structure of the upper mantle transition zone, from 400 to 700 km depth, which is key to understanding the mode of convection within the Earth's mantle as well as the chemical composition of the Earth. In this project, the plan will be to delineate seismic structure of the transition zone associated with Japanese subduction zones using upper mantle (triplicated P and S waveforms recorded at regional stations. Three major issues debated recently will be considered: 1) what velocity anomalies are associated with the subduction zones in the transition zone; 2) whether the subducting slabs flatten at the bottom of the transition zone or extend into the lower mantle; and 3) whether the seismic structure derived for the upper mantle supports a model of chemical layering or one with discontinuities due to temperature-dependent phase transitions approximately at 410 km, and possibly at about 525 km. *** ??