1D Multiscale Full Waveform Tomography Lab

By Chaiwoot Boonyasiriwat


Theory: Given an input trace P(zg, t; zs), 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 < cmin/fpeak/15 and dt < 0.6*dx/cmax.
  4. Modify the code to use CG method and Quasi-Newton method.
  5. Repeat the previous steps with 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.