Seismic full waveform inversion (FWI) is a model-based prestack inversion method. A misfit function (error, cost or objective function) between the observed seismic gathers and the suitably created corresponding model gathers is minimized using nonlinear optimization methods (Lailly in The seismic inverse problem as a sequence of before stack migrations, pp 206–220, 1983; Tarantola in Geophysical Prospecting 32:998–1015, 1984a; Tarantola in Inverse problem theory. Elsevier Science Publishers, 1987; Tarantola in Inverse problem theory and model parameter estimation. SIAM, 1995).