Title: Quasi-Axisymmetric Finite-Difference Method for Realistic Modeling of Regional and Global Seismic Wavefield — Review and Application —
Abstract: In this chapter, we describe recent developments of forward-modeling techniques for accurate and efficient computation of the realistic seismic wavefield. Our knowledge on the Earth’s interior has been enhanced by mutual progress in observation and numerical methods. Since the first time-recording seismograph was built in Italy in 1875 (Shearer, 1999), the recorded seismic dataset has been growing at an almost exponential rate. Such a massive amount of seismic waveform data should be interpreted with consideration of the seismic source mechanism and Earth’s inner structure, which explain each crest or trough in observed waveform traces. This interpretation can be achieved by forward modeling of seismic waveforms. In addition, recent progress in computation capacity has enabled investigation of the Earth’s inner structure via waveform inversion, an inverse problem minimizing the difference between observed and synthetic seismograms. This method requires iterative computations of synthetic seismograms for each structural model renewal in theminimization process, so we need a forward modeling technique that produces accurate waveforms with small computation time and memory.