1. A method for generating a time lapse difference image, comprising: performing a first seismic survey; performing a second seismic survey after a predetermined amount of time has lapsed between the first seismic survey and the second seismic survey, wherein the shot times and the shot positions of the second seismic survey are substantially the same as the shot times and the shot positions of the first seismic survey; processing seismic data generated by the first seismic survey to generate a first image; processing seismic data generated by the second seismic survey to generate a second image; and computing a difference between the first image and the second image.