Full Waveform Inversion Lab

by Chaiwoote Boonyasiriwat


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Objective: Learn how to run full waveform inversion code.

Skill Learned: Implementation, and understand MPI code for full waveform inversion.

Procedure:

  1. Download MMI package to your Linux desktop. Downlload, compile and run MMI code on Shaheen.

  2. Download Marmousi.tar.gz, which contains Marmousi model and job files for full waveform modeling and inversion. Copy this file into scratch directory on shaheen. Extract Marmousi by running tar zxvf Marmousi.tar.gz on your command prompt. You will see the directories and files below.

modeling_dd: the directory used for seismic data modeling

inversion_dd: the directory used for full waveform inversion

vel_nx850_nz156_dx20.dat: Marmousi velocity model

coord.dat: coordination of sources and geophones

  1. To create the synthetic seismic data, you need to change your current directory to modeling_dd. There are four files and one directory inside.

parfile.ini: parameter file for initial code

init.sh: job file for running initial code

parfile: parameter file for modeling code

run.sh: job file for running modeling code

CSG: directory for seismic modeling data

  1. Change the file path in the job files to your own path, and submit job file to shaheen by running.

llsubmit init.sh. After it finishes, run another job file by llsubmit run.sh. You can check seismic modeling data in CSG directory by

xwigb < csg100.dat n1=4001 perc=99

  1. To invert the synthetic seismic data, you need to change your current directory to inversion_dd. There are three files inside.

parfile: parameter file for inversion code

velpad_smooth.dat: initial velocity model for inversion code

run.sh: job file for running inversion code

  1. You can view the inverted velocity mode by xwigb < vel1.dat n1=4001 perc=240

Exercises:

  1. Create the synthetic data using the forward modeling code.

  2. Invert the synthetic data generated by the full waveform code.

  3. Change the initial velocity model and see what's the difference in the inverted velocity mode.