Inversion = migration + tomography

Seismic inversion, broadly enough defined, is equivalent to doing migration and reflection tomography simultaneously. I propose that a nonlinear iterative inversion that updates a varying background velocity obtains all wavenumbers that are resolvable separately by migration and tomography. Synthetic examples verify the theoretical predictions and show that reflector locations and interval velocities can be obtained simultaneously even when there is no prior knowledge of reflector location. -from Author