<p>Methods for generating a time lapse difference image. In one implementation, the method includes estimating a trace in a first seismic survey data set at each trace coordinate of a second seismic survey data set (430), estimating a trace in the second seismic survey data set at each trace coordinate of the first seismic survey data set (435) and calculating trace differences between the first seismic survey data set and the second seismic survey data set at each trace coordinate of the first seismic survey data set and the second seismic survey data set (440).</p>
