Comparison of acoustic full waveform tomography in the time - and frequency - domain

For better parameter estimation, both in active source and earthquakes seismology, we need to exploit the richness of full seismic waveforms. Full waveform tomography (FWT) is a powerful method to reach this goal. Although first implementations in the 1980's were conducted in the time-domain by Tarantola, the frequency-domain version of FWT developed in the 1990's by G. Pratt and coworkers has now emerged as an efficient imaging tool. The main advantage of the frequency-domain approach is the possibility of starting the inversion at low frequencies (large scale structures) and then moving to higher frequency compounds (smaller scale structures), thereby realizing a multiscale approach. The main advantage of the time-domain method is the efficient parallelization by domain decomposition leading to a significant speedup on parallel computers. In this study, we demonstrate the performance of our parallel acoustic time-domain code. We present the results for a very complex example - a random medium model. Last but not least, we compare our time-domain inversion results with the frequency-domain results calculated using the FULLWV code by G. Pratt et al.