1 Inversion of seismic waveforms for 3-D earth structure us- ing vector-parallel supercomputers

The three-dimensional (3-D) seismic images of the earth’s in erior provide important keys to un-derstand and numerically model the earth’s dynamics. We have been developing numerical codes to simulate seismic waves traveling in the earth’s int rior and applying them to waveform inver-sion of observed seismic waveform data to determine 3-D seismic earth structure [e.g., 1, 2]. Al