Following a resolution test of tomography of the AVF using global teleseismic sources, we perform a separate test considering the local events with Nick Rawlinson’s FMTOMO package.

The events considered have paths that involve direct and up-going waves (little p and s, as opposed to P and S in the teleseismic tomography).

681 hypocentres and seismic stations in and around the AVF.

A depth slice at 90km resolves the checker-board pattern under the stations. Smearing is apparent in the latitudinal and longitudinal slices. There isn’t much difference in terms of the results between p- and s-wave inversion.

Using a finer checker-board

In order to resolve smaller scale structure in the subsurface,  a finer scale checker-board was tested.

The first 60 km in depth seem resolved in this test. However, deeper inversion results mostly add up to the effect of smearing. Unlike the S-wave results for teleseismic tomography, s-waves seem to benefit our regional tomography results.

Summary

• Features on the order of  ~50km, are possibly recoverable up to 150 km deep, 174.2 to 176.4 longitudinally, and -36 to -37.8 latitudinally.
• Features half this size may be retreived up to 60 km down, 174.2 to 177.2 longitudinally, and -36.6 to -37.4 latitudinally.
• S wave tomography shows a better lateral resolution for the periphery of the stations. Most prominently with the finer scale checker-board.