Determination of the Deep Structure of Descending Lithospheric Slabs from Their Effects on Seismic Body Waves

这项研究解决了大规模地球动力学中最重要的问题之一，即俯冲岩石圈一旦渗透到最深地震的深处以下的命运。本研究将从深板结构对地震纵、横波波形的影响出发，探讨深板结构对地震纵、横波波形的影响。这些影响包括旅行时间提前、散焦、多路径和衍射。数字记录的纵波和横波将与用理论方法计算的三维板结构合成的地震记录进行比较分析。650 km地震活动断裂带下岩石圈板块的下降结构对认识地幔黏性结构和整个地幔对流过程具有重要意义。因为对流是板块构造和世界地震活动背后的驱动力，这项工作是对国家地震危害减少计划的贡献。

This research addresses one of the most important problems in large-scale geodynamics, the fate of subducted lithosphere once it has penetrated below the depths of the deepest earthquakes. The work will investigate deep slab structure from its effects on the waveforms of seismic P and S waves. These effects include travel time advance, defocusing, multipathing, and diffraction. Digitally recorded P and S waves will be analyzed by comparison with seismograms synthesized in three dimensional slab structures computed by theoretical methods. The structure of the descending lithospheric slabs below the cutoff in seismicity at 650 km depth is important to the understanding of the viscosity structure of the mantle and processes of whole mantle convection. Because convection is the driving force behind plate tectonics and the world's earthquake activity, this work is a contribution to the National Earthquake Hazard Reduction Program.