9628351 Jordan This research involves the determination of the structure of the Earth's mantle in Australasia, eastern Asia, and the western Pacific through a series of seismological experiments that begin with a three-dimensional, high resolution tomographic study. Motivation for the study comes from new stations in the study area and new inversion techniques for a more diverse collection of seismic phases. Frequency dependent travel times of body waves, guided waves, and surface waves can now be derived from a self- consistent analysis of three-component seismograms recorded at short epicentral distances, which makes them ideally suited for regional tomography. Combination of these data with the band- centered travel times of zeroth-order and first-order ScS reverberation phases, allows inversion for mantle discontinuity topography and lateral variations in polarization anisotropy. The resulting model has a direct bearing on the mode of mantle convection which is the driving force for plate tectonics and earthquakes. This research is a component of the National Earthquake Hazard Reduction Program. ***
