We presented and tested a method to invert
for all wavelengths of the velocity model simultaneously
from seismic reflection data.
The method does not suffer from the global convergence limitations
of conventional full waveform inversion.
The method is based on the extension of the velocity model
to subsurface offsets and on the addition of a reflection focusing objective
function to the conventional FWI data-fitting objective function.
The Marmousi model numerical tests indicate that the method
can robustly converge to very accurate models when FWI fails.
The numerical solution of the wave equation with the extended
velocity is computationally expensive.
The excellent results, and the computational expense, justify the search
of an approximate solution that still enables the simultaneous solution
for all wavelengths in the model.
We present such approximation in a companion report
(Almomin and Biondi, 2012).