Synthetic Examples

The synthetic examples use known checkerboard models to verify the complete SurfATT workflow: generate synthetic travel times, invert those data, and compare the recovered model with the target model.

All examples are taken from the SurfATTPP/examples directory.

Example	Model parameters	Input data	What it tests
00 — Isotropic checkerboard	$V_s$	Rayleigh phase velocity	Recovery of isotropic velocity perturbations
01 — Azimuthal-anisotropy checkerboard	$V_s$ , $G_c$ , and $G_s$	Rayleigh phase velocity	Recovery of velocity and horizontal fast-axis structure
02 — Radial-anisotropy checkerboard	$V_{SV}$ , $V_{SH}$ , and $\zeta$	Rayleigh and Love phase velocity	Recovery of velocity and radial-anisotropy strength

Common workflow

Each example follows the same two-stage workflow:

SURFATT_cb_fwd adds a known checkerboard perturbation to the initial model and calculates synthetic travel times.
SURFATT_tomo treats those travel times as observations and attempts to recover the target model.

Run an example from its own directory:


cd examples/<example-directory>
bash run_this_example.sh

The scripts use eight MPI processes by default. Change NPROC in run_this_example.sh to match the resources available on your system.

Comparing the results

The forward and inversion steps write their results to OUTPUT_FILES/. The three files used most often for validation are:

initial_model.h5 — the unperturbed starting model
target_model.h5 — the known checkerboard model used to create the synthetic data
final_model.h5 — the model recovered by the inversion

Each example includes a Jupyter notebook that compares the target and recovered structures.