A method for exploring a geological formation estimates a multiple-inclusive source wavelet and a reflectivity model by performing an inversion minimizing the difference between the shot records and modeled shots. The modeled shots, that include primaries and multiples, are obtained by propagating up-going and down-going wavefields through an input velocity model, which is not updated during the inversion. The shot records are converted into a geological product suitable for hydrocarbon exploration in the geological formation using the multiple-inclusive source wavelet and the reflectivity model.