Abstract: The invention relates to a method for seismic exploration, comprising the steps of controlling a plurality of sources so that they emit a plurality of seismic waves in a subsurface zone to be explored, each source successively occupying a plurality of emitter positions, producing for each emission a signal representative of the emission, and recording the position of the source and the instant at which the emission starts, continuously recording by means of seismic sensors the composite signals reflected by the medium in response to said emissions, and carrying out shot point migration, on the one hand, from a reflected wave field constituted of said composite signals and respective sensor positions, and on the other hand, from an incident wave field constituted of signals representative of the emissions, source positions and start emission instants, so as to obtain a seismic image.

Abstract: Method of processing seismic data representative of at least one wavefield, characterized in that local harmonic components of the wavefield are determined at a given point P of the subsurface by implementing a recurrent processing according to which a harmonic of rank n+1, n being a positive integer, is determined as a function of one or more harmonics of rank n or lower to which is applied at least one filtering which depends on at least one local parameter at the point P, this local parameter being chosen from among the components of the wavevector, the frequency of the wavefield, the local velocity, the local anisotropy parameters or any combination of these various parameters.

Abstract: A method of seismic prospecting offshore by means of at least one pair of hydrophone-geophone sensors disposed at the water bottom, in which a sound source at the surface of the water emits a sound signal and the sensors at the water bottom take hydrophone and geophone recordings H and G, the method comprising the following various steps:a filtered signal is determined such that:M=H.sub..DELTA. -G.sub..SIGMA.withH.sub..DELTA. =1/2(H-H.sub.R)andG.sub..SIGMA. =1/2(G+G.sub.R)where H.sub.R and G.sub.R correspond respectively to the recordings H and G propagated over a go-and-return path through the layer of water; andthe data obtained in this way is processed to deduce therefrom information about the geology of the subsoil.

Abstract: The invention relates to a seismic prospection method in which a seismic disturbance is generated in the sub-soil and sensors are used to pick up seismic data, the seismic data being processed to deduce useful information concerning the geology of the sub-soil, the seismic data containing a signal y.sub.0 that is to be isolated, said signal y.sub.0 being present in the seismic data embedded in an additive signal. The method comprises the steps consisting in: 1) for .alpha. given integer p, computing a prediction error filter a having p coefficients and providing best cancellation of the signal y.sub.0 ; 2) applying the self-deconvoluted prediction error filter to the seismic data to obtain filtered data in which the signal y.sub.0 is absent; and 3) subtracting the filtered data from the initial data to obtain processed data containing the signal y.sub.0 without the additive signal.

Abstract: A processing method for calibrating at least one pair of hydrophone-geophone sensors disposed on a water bottom and used in seismic prospecting processing in which a sound source emits a signal into the water and the sensors at the water bottom pick up hydrophone and geophone recordings H and G, wherein calibration is applied to the recordings to minimize, in a time window beyond a theoretical extinction time, the energy of a signal S which is determined as a function of the hydrophone and geophone recordings and which corresponds to the source signal propagated through the layer of water to the sensor.

Abstract: The present invention relates to a method of extrapolating a set of traces recorded by means of an array of sensors, in the context of a geophysical prospecting process, the method comprising the steps consisting in: i) approximating a minus Laplacian L.sub.0 (k.sub.x,k.sub.y)=k.sub.x.sup.2 +k.sub.y.sup.2 by the sum of two one-dimensional filters; and ii) approximating an extrapolation operator F.sub.0 by a polynomial of the minus Laplacian L.sub.0. The invention also provides a system for geophysical prospecting.