9706201 Song This research involves the expansion of previous findings concerning the differential rotation of the earth's inner core. Waveform modeling and differential time measurements of core phases (PKP) have successfully led to new insights on both the P- wave anisotropy, structure and rotation of the inner core. The approach of using relative observations (waveforms, differential times) with a common source eliminates the concern about uncertainties in source origin time, excitation, mislocation, and velocity uncertainties in the crust and upper mantle under the source and receiver. More differential data will be assembled to invert the anisotropy/attenuation structure of the inner core in a frame of a spinning inner core. ***
