I am using the MATLAB script BLIMP (Ferguson and Margrave, 1995) to invert SH-wave data for shear-impedance. Is this inversion scheme a linear or non-linear process? There are certainly non-linear calculations occurring (i.e. integration and exponentiation), but I am unsure if that automatically qualifies it as non-linear.
For whatever answer you have, please provide some reference for me to track down.