Abstract: In order to acquire seismic data relative to an underground area beneath the sea, seismic waves are emitted in an emission direction forming an angle ? with the vertical using at least one seismic source submerged at a depth d. A seismic signal is collected following the emission of the seismic waves and the propagation of same underground with a view to processing same. In one embodiment of the method, in order to overcome the major problem linked to the depth limit encountered by seismic sources, the processing of the seismic signal comprises a summation of a plurality of terms including the seismic signal and the seismic signal delayed by ?T=2d·cos ?/V, in which V is the speed of propagation of the seismic waves in water.