A subsurface imaging method for processing geophysical survey data, the method carried out by a computer and comprising: obtaining initial signals from a geophysical survey acquired with multiple geophysical energy sources (14, 16) actuated in a plurality of firing sequences, each sequence having a known, different time delay between a seismic signal recording start time and a firing time of each source; forming gathers of the initial signals, each gather comprising signals acquired from multiple firing sequences; and for each gather: applying a coherent/incoherent energy separation operation to the signals to determine coherent energy signals and incoherent energy signals, the coherent energy signals serving as an initial estimate of a first source wave field; applying the coherent/incoherent energy separation operation to the incoherent signals to determine coherent energy signals and incoherent energy signals, the coherent energy signals serving as an initial estimate of a second source wave field; generating first source quieted signals representing the initial signals minus a current estimate of the second source wave field; applying the coherent/incoherent energy separation operation to obtain a refined estimate of the first source wave field from the first source quieted signals; calculating second source quieted signals representing the initial signals minus the refined estimate of the first source wave field; using the coherent energy separation operation to obtain a refined estimate of the second source wave field from the second source quieted signals; deriving a subsurface image from refined estimates of the first and second source wave fields; and rendering the subsurface image in a perceptible form. obtaining initial signals from a geophysical survey acquired with multiple geophysical energy sources (14, 16) actuated in a plurality of firing sequences, each sequence having a known, different time delay between a seismic signal recording start time and a firing time of each source; forming gathers of the initial signals, each gather comprising signals acquired from multiple firing sequences; and for each gather: applying a coherent/incoherent energy separation operation to the signals to determine coherent energy signals and incoherent energy signals, the coherent energy signals serving as an initial estimate of a first source wave field; applying the coherent/incoherent energy separation operation to the incoherent signals to determine coherent energy signals and incoherent energy signals, the coherent energy signals serving as an initial estimate of a second source wave field; generating first source quieted signals representing the initial signals minus a current estimate of the second source wave field; applying the coherent/incoherent energy separation operation to obtain a refined estimate of the first source wave field from the first source quieted signals; calculating second source quieted signals representing the initial signals minus the refined estimate of the first source wave field; using the coherent energy separation operation to obtain a refined estimate of the second source wave field from the second source quieted signals; deriving a subsurface image from refined estimates of the first and second source wave fields; and rendering the subsurface image in a perceptible form. applying a coherent/incoherent energy separation operation to the signals to determine coherent energy signals and incoherent energy signals, the coherent energy signals serving as an initial estimate of a first source wave field; applying the coherent/incoherent energy separation operation to the incoherent signals to determine coherent energy signals and incoherent energy signals, the coherent energy signals serving as an initial estimate of a second source wave field; generating first source quieted signals representing the initial signals minus a current estimate of the second source wave field; applying the coherent/incoherent energy separation operation to obtain a refined estimate of the first source wave field from the first source quieted signals; calculating second source quieted signals representing the initial signals minus the refined estimate of the first source wave field; using the coherent energy separation operation to obtain a refined estimate of the second source wave field from the second source quieted signals; deriving a subsurface image from refined estimates of the first and second source wave fields; and rendering the subsurface image in a perceptible form.