1D Multiscale Full Waveform Tomography Lab

By Chaiwoot Boonyasiriwat

Theory: Given an input trace P(z_g, t; z_s), find a velocity profile c(z) by multiscale waveform tomography (see Tarantola, 1984; Bunks et al., 1995).

Objective: Learn the multiscale waveform tomography in time domain.

Procedure:

1. Load the following Matlab scripts: ricker.m, modeling.m, fd1d.m
2. Execute the command "fd1d".
3. Modify the code to use a 3-level multiscale approach by using 15-Hz peak-frequency data. To avoid numerical dispersion and instability, dx < c_min/f_peak/15 and dt < 0.6*dx/c_max.
4. Try different velocity profiles.

References:

• Tarantola, A., 1984, Inversion of seismic reflection data in the acoustic approximation: Geophysics, 49, 1259-1266.
• Bunks, C., Saleck, F. M., Zaleski, S., and Chavent, G., 1995, Multiscale seismic waveform inversion: Geophysics, 60, 1457-1473.