Abstract: A universal seismic data acquisition module includes independent environmental isolation chambers for essential signal processing circuitry and for cable connection unions. Cable connection unions are rapidly replaced without opening the main protective chamber. Different connector types required for the many data transmission cable designs needed to service a wide range of survey conditions are more easily accommodated than in conventional single chamber designs. The module is rugged and suitable for operating in a wide range of physical environments including lake or sea immersion to substantial water depths, desert, arctic and others. Need for investment in multiple module types for varying survey conditions is thereby reduced without compromising capacity.

Abstract: A method of de-ghosting seismic data acquired in a marine seismic survey comprises estimating ?zp (where p is the fluid pressure) from a time-derivative of p and a derivative of p in a horizontal direction such as the x-direction. The time-derivative of p and the derivative of p in the horizontal direction can be readily obtained from the acquired seismic data, and are used to provide an improved estimate of ?zp which, in general, cannot be directly determined from the acquired seismic data. Once ?zp has been estimated it can be used to de-ghost the acquired seismic data.

Abstract: A seismic sensor cable is disclosed. The cable includes an outer jacket disposed on an exterior of the cable. The outer jacket excludes fluid from entering an interior of the cable. A reinforcing layer disposed within the outer jacket, which includes at least one electrical conductor disposed therein. An inner jacket is disposed within the reinforcing layer, and at least one electrical conductor disposed within an interior of the inner jacket. Some embodiments include at least one seismic sensor electrically coupled to the at least one electrical conductor disposed in the reinforcing layer In some embodiments a housing is disposed over the electrical coupling of the sensor to the conductor. The housing is molded from a polyurethane composition adapted to form a substantially interface-free bond with the cable jacket when the polyurethane cures.

Abstract: The invention provides a method of determining the orientation of a seismic receiver (4, 6) from seismic data acquired at the receiver (4, 6). The determined orientation can be taken into account in subsequent analysis of the seismic data. This avoids inaccuracies that can occur if the receiver orientation is estimated. In a preferred embodiment the horizontal spatial derivatives of the pressure measured at the receiver are used in the determination of the orientation of the receiver. These may be calculated on either the source side or the receiver side. These are combined with horizontal components of the particle displacement, velocity or acceleration (or a higher time-derivative of the particle displacement). Alternatively, horizontal spatial derivatives of the particle displacement measured at the receiver may be used in place of the horizontal spatial derivatives of the pressure.

Abstract: A method is disclosed for processing seismic data. The method includes determining a position of a seismic energy source and seismic receivers at a time of actuation of the source. A velocity of the seismic receivers with respect to the source position is determined at the time of actuation. An offset of the receivers is corrected using the velocity. A moveout correction is determined for the signals detected by the sensors based on the corrected offset and a velocity of earth media through which seismic energy passed from the source to the sensors.

Abstract: A method for making a time-lapse seismic survey in a marine environment, the method designed to eliminate multiple surface reflections and changes in sea state and conditions. Seismic sources and receivers are positioned at predetermined conditions for a first set of data in which at least two sets of seismic signals are recorded at each receiver, proximate in time, such that there are insignificant changes in the subsurface formation. At a later point in time the seismic source(s) and receiver(s) are positioned at the same place when the first seismic data set was generated. A seismic source emits a sound wave and the seismic receiver receives what will be called a “monitor signal” and the two-way water travel time is again determined. A model is then developed for the first and second seismic data sets in that includes the subsurface signal, changes in the subsurface signal and the effect of multiple reflections.

Abstract: A method for seismic surveying is disclosed which includes towing a first seismic energy source and at least one seismic sensor system. A second seismic energy source is towed at a selected distance from the first source. The first seismic energy source and the second seismic energy source are actuated in a plurality of firing sequences. Each of the firing sequences includes firing of the first source, waiting a selected time firing the second source and recording signals generated by the seismic sensor system. The selected time between firing the first source and the second source is varied between successive ones of the firing sequences. The firing times of the first and second source are indexed so as to enable separate identification of seismic events originating from the first source and seismic events originating from the second source in detected seismic signals.

Abstract: A method for estimating near-surface material properties in the vicinity of a locally dense group of seismic receivers is disclosed. The method includes receiving seismic data that has been measured by a locally dense group of seismic receivers. Local derivatives of the wavefield are estimated such that the derivatives are centered at a single location preferably using the Lax-Wendroff correction. Physical relationships between the estimated derivatives including the free surface condition and wave equations are used to estimate near-surface material properties in the vicinity of the receiver group. Another embodiment of the invention is disclosed wherein the physical relationships used to estimate material properties are derived from the physics of plane waves arriving at the receiver group, and the group of receivers does not include any buried receivers.

Abstract: The present invention provides methods to be used in seismic data processing to address problems encountered during data acquisition. The present invention provides a multi-step process to reduce aliasing of seismic data along time slices.

Abstract: A method of acquiring and processing seismic data including: acquiring digitized seismic data associated with a plurality of moving receiver points using a plurality of seismic sensors; attenuating noise in the moving receiver point based digitized seismic data using digitized seismic data associated with a plurality of nearby receiver points; transforming noise attenuated moving receiver point based digitized seismic data into stationary receiver point based digitized seismic data; and recording noise attenuated and transformed digitized seismic data associated with stationary receiver points having an average spatial separation interval at least twice the average moving receiver point spatial separation interval. This method is particularly effective at attenuating coherent low frequency noise and correcting for the receiver motion effect in marine seismic data.

Abstract: A system and method of creating a filter for use with locally dense seismic data is disclosed. The method includes obtaining survey geometry characteristics from a locally dense seismic survey. A filter is designed which uses spatial derivatives of the wavefield of order between (1) and the maximum order of spatial derivatives of the wavefield that can be estimated within a group. The filter can be designed so as to separate up/down going components, p/s components, or both up/down and p/s components. Partial derivatives in space and time of the wavefield can be calculated, using, for example, a taylor series expansion as an approximation. The seismic data is filtered by combining estimated near surface material properties, the seismic data, and the calculated partial derivatives.

Abstract: The present invention provides a method for analyzing traces collected along a plurality of adjacent sail lines in a marine seismic survey area. The method comprises selecting a plurality of trace groups, at least one trace in each group sharing a common midpoint with at least one trace from another group, determining an initial zero-offset travel time for each trace in the trace groups, and generating a plurality of updated zero-offset travel times and a plurality of time corrections for the trace groups using a pre-selected function of the initial zero-offset travel times.

Abstract: The present invention provides a method for reducing water bottom reflection time differences. The method includes selecting a plurality of trace groups, each trace having an offset from a midpoint and a water bottom reflection time. The method also includes determining a rate of change of the water bottom reflection time of each trace and generating a model water velocity and a model water bottom reflection time for each trace midpoint using a preselected function of the water bottom reflection times and the rates of change. Furthermore, the method includes generating a plurality of water bottom reflection time corrections for the traces in each trace group using a pre-selected function of the water bottom reflection times, the model water bottom reflection times, the model water velocities, and the trace offsets.

Abstract: A method is disclosed for marine seismic surveying in which a seismic signal is detected in a body of water with a motion sensor and a pressure sensor positioned at a location proximate the bottom of the body of water. Seismic signals are detected with pressure sensors positioned in one or more streamer cables being towed in the body of water near the location proximate the bottom of the water at which a motion sensor and a pressure sensor are positioned. The signals detected by the motion sensor and pressure sensor positioned proximate the bottom of the body of water are used for calibrating the seismic signals detected with the pressure sensors positioned in the streamer cables.

Abstract: A seismic data acquisition module includes a motherboard that is environmentally protected as a independent unit by an integral sheath, envelope or encapsulating cover. The motherboard unit is suitably configured for rapid and frequent manual removal from the interior cavity of a protective outer housing for compact and more secure packaging as well as more convenient transport over great distances, if necessary, to successively different survey sites. At a new survey site, the motherboard units may be inserted into more bulky but also more rugged or waterproof outer housings that are provided with environmentally tight cable connectors. The outer housings, having a capital value of only a fraction of the electronic motherboard units, may have arrived at the new site at a different time and may even be distributed in the new survey field at the time the motherboard units arrive.

Abstract: A seismic signal is represented as a combination of a geologic signal and a noise signal. The representation of the seismic signal is decomposed into a linear combination of orthonormal components. One or more components are identified in which the geologic signal and the noise signal are uncorrelated. The noise signal is expanded as a product of an unknown noise amplitude modulation signal and a known noise spatial periodicity signal at the identified components. The expansion is solved for an estimate of the noise amplitude modulation signal at the identified components. The noise signal is estimated by multiplying the estimated noise amplitude modulation signal by the noise spatial periodicity signal. The estimated noise signal can be removed from the seismic signal to generate an estimate of the geologic signal.

Abstract: Seismic detection apparatus comprising seismic detection means capable of detecting a plurality of seismic components over a defined tetrahedral volume is provided. The seismic detection means comprises four three-component geophones. Seismic data acquired by the geophones is processed to separate P-wave components from S-wave components. The geophones are spaced apart by distances smaller than the wavelength of the detected seismic components. The apparatus may be used on surface or in a marine environment or transition zone. A method of processing seismic data is also provided comprising acquiring seismic data relating to a wavefield over a selected volume of acquisition, and measuring the curl and divergence of the wavefield from the seismic data, to thereby identify seismic components within the seismic data. Additionally, an apparatus and method for hydrocarbon exploration is disclosed for using three or more seismic receivers placed in a plane and spaced closely to each other.

Abstract: The invention provides a method of processing seismic data acquired using a seismic source array that emits, in use, a seismic wavefield having a frequency spectrum that does not contain a source ghost at a non-zero frequency within the seismic bandwidth. This eliminates source-side ghost reflections. The method further comprises processing the acquired seismic data thereby to attenuate the effect of ghost reflections in the seismic data, and this eliminates receiver-side ghost reflections.

Abstract: A method is disclosed for attenuating noise from marine seismic signals caused by a noise in the water. The method includes determining an arrival time of a noise event at each of a plurality of seismic sensors, estimating a position of the noise source from the arrival times, and attenuating the noise event from the signals detected by the seismic sensors.

Abstract: A network distributed seismic data acquisition system comprises seismic receivers connected to remote acquisition modules, receiver lines, line tap units, base lines, a central recording system and a seismic source event generation unit synchronized to a master clock. One or more high precision clocks is added to the network to correct for timing uncertainty associated with propagation of commands through the network. Seismic receivers and seismic sources are thereby synchronized with greater accuracy than otherwise possible. Timing errors that interfere with the processing of the seismic recordings are greatly reduced, thus enabling an improvement in subsurface geologic imaging.

Abstract: A method of processing multi-component seismic data acquired at a receiver comprises determining a suitable decomposition scheme to use. This makes use of the existence of pairs of wavefield components that are uncoupled from one another. If there is no physical coupling between first and second wavefield components, the first and second components should not arrive at a receiver location at the same time.

Abstract: A method for generating a model of a portion of the floor of a body of water from a plurality of depth measurement sources includes determining an overlap of any of the plurality of depth measurement sources with another depth measurement source and generating a relative shift between any two depth measurement sources that overlap. For each depth measurement source that overlaps with at least one other source, generating an overall shift based on the generated relative shifts. The method also includes generating a desired grid having a plurality of grid nodes and generating a model depth at a plurality of the grid nodes based, at least in part, on a global shift for the measurements of the plurality of sources based on the relative shift. Further, an output is generated of all model depths at respective grid nodes.

Abstract: A method is provided for analyzing received seismic signals which are received from a plurality of seismic sensors in response to operation of an acoustic source during a marine seismic survey. The seismic sensors are located at different offsets from the acoustic source. The method comprises the steps of selecting a time window within a particular seismic signal which frames a relatively well-defined event represented in the signal. The particular seismic signal is received from a particular seismic sensor. The method further comprises determining a receiver ghost notch frequency from an amplitude/frequency spectrum of the seismic signal in the window and deriving from the receiver ghost notch frequency an estimate of a height of a water column above the particular seismic sensor which generated said particular seismic signal.

Abstract: A method for seismic surveying is disclosed which includes towing a first seismic energy source and at least one seismic sensor system. A second seismic energy source is towed at a selected distance from the first source. The first seismic energy source and the second seismic energy source are actuated in a plurality of firing sequences. Each of the firing sequences includes firing of the first source, waiting a selected time firing the second source and recording signals generated by the seismic sensor system. The selected time between firing the first source and the second source is varied between successive ones of the firing sequences.

Abstract: A seismic data acquisition method and system are shown. The method acquires seismic data using an acoustic source capable of producing a seismic signal and an acoustic receiver in an area having periodic acoustic interference. The method includes sensing a time window in which the periodic acoustic interference at the acoustic receiver is substantially attenuated, and adjusting the acoustic source's discharge time so a desired portion f a seismic signal produced by the acoustic source arrives at the acoustic receiver within a subsequent time window.

Abstract: Measurements made by a cross-dipole acoustic logging tool in a borehole are processed to determine the principal directions of azimuthal anisotropy of a subsurface formation. Measurements indicative of azimuthal resistivity variations are also made with a multicomponent induction logging tool. These electrical measurements are processed using the principal direction determined from acoustic measurements to give an estimate of azimuthal resistivity variations. Based on modeling results, azimuthal resistivity variations are interpreted to estimate a fracture depth in the rock for known fluids therein.

Abstract: The claimed invention is an apparatus, method and system for optimizing bandwidth utilization of demodulators in a system for seismic signal processing, wherein the apparatus comprises demodulators having bandwidths, wherein one demodulator's bandwidth is greater than another demodulator's bandwidth. The apparatus further comprises an optical switch coupled to a fringe rate detector, wherein optical fibers bear seismic signals having fringe rates detected by the fringe rate detector. The optical signals are switched among the demodulators in dependence upon the fringe rates. Further, the claimed invention is an apparatus, method and system for active gain ranging of demodulated signal outputs.

Abstract: A method of compensating for seismic receiver motion in a marine seismic survey wherein at least one receiver is towed behind a moving seismic vessel comprises producing an acoustic energy wave at a seismic source, and recording the reflection arrival time t2 of the acoustic energy wave at the one receiver. The offset x between the source and the one receiver is determined. The normal moveout velocity V for the acoustic energy, and the velocity VB of the seismic vessel are also estimated. A corrected reflection arrival time t1 , of the acoustic energy wave is then determined by applying a time correction to the recorded reflection arrival time t2. The time correction is a function of the offset x, the normal moveout velocity V, and the velocity VB of the seismic vessel. The method is applicable to a plurality of receivers, whether the receivers are arranged in a single sensor acquisition system or hardwired to form receiver groups.

Abstract: In one embodiment of the present invention, a method for processing a scattered acoustic wavefield is provided. The scattered acoustic wavefield is received by at least two receivers. These receivers are offset and located at approximately the same depth. The method comprises transforming the scattered acoustic wavefield to the frequency domain. The method also comprises transforming the scattered acoustic wavefield from the frequency domain to the spectral domain. The method also comprises deghosting the scattered acoustic wavefield in the spectral domain. The method further comprises transforming the substantially deghosted transformed acoustic wavefield to the space-time domain.

Abstract: A method of compensating for seismic receiver motion in a marine seismic survey wherein at least one receiver is towed behind a moving seismic vessel comprises producing an acoustic energy wave at a seismic source, and recording the reflection arrival time t2 of the acoustic energy wave at the one receiver. The offset x between the source and the one receiver is determined. The normal moveout velocity V for the acoustic energy, and the velocity VB of the seismic vessel, are also estimated. A corrected reflection arrival time t1 of the acoustic energy wave is then determined by applying a time correction to the recorded reflection arrival time t2. The time correction is a function of the offset x, the normal moveout velocity V, and the velocity VB of the seismic vessel. The method is applicable to a plurality of receivers, whether the receivers are arranged in a single sensor acquisition system or hardwired to form receiver groups.

Abstract: A method of migrating seismic event data in the presence of a vertically time-varying velocity field defined by a migration velocity finction is provided. The method comprises approximating a migration velocity function by constant stepwise stage velocities. The seismic event data is time stretched and is then successively migrated using residual velocities. After the seismic event data is fully migrated, the effect of time stretching is removed by time unstretching the fully migrated seismic event data by a reverse operation to obtain a finally migrated seismic event data.

Abstract: A device for canceling non-acoustic self-noise associated with mechanically induced vibrations in sensor arrays and associated methods are described. The method utilizes the isolation of a vibration reference via digital beamforming to non-acoustic wavenumber space. This technique produces an interference reference measurement which is sensitive only to vibrations propagating within an array body and independent of acoustic signals propagating in surrounding medium.

Abstract: A data acquisition system has a central station connected to a plurality of nodes over a network. Each node is connected to receive signals from one or more sensors ad each is configured to have substantially the same transmission delay to said central station. The central station is configured to notify all nodes of an event time at which a data event, such as a seismic shot, occurred.

Abstract: A method and an apparatus are provided for matching the response of hydrophones 22 to the response of geophones 24 and significantly reducing response variations between hydrophones caused by inherent characteristics. The method includes the steps of determining a capacitance 66 for each of the hydrophones 22 in an operating environment, configuring a filter 36 based on the capacitance 66, and modifying a response of a channel of the hydrophone 22 using the filter 36. The apparatus includes an acquisition unit 20 having a geophone 24 and a hydrophone 22, a recording unit 30, a processing unit 31 and a filter 36 for correcting for variation between hydrophones 22 and changing a first order low frequency response of the hydrophone 22 to appear like a second order response like that of the geophone 24.

Abstract: A variable length data packet in a seismic system includes a fixed-length data portion and a variable-length data portion, the amount of data in the variable-length portion depending on the number of active channels. The data packet identifies the number channels which are in operation in the system, which may be the same or fewer than the number of installed channels. This signals the central recorder as to the length of the block of data in the data packet which includes seismic data. This feature permits the scaling of the system to accommodate varying numbers of channels, without reconfiguring the system. In another aspect, a method of sending data in a data system having a plurality of installed channels includes the steps of determining the number of active channels; assembling a packet of data comprising a fixed-length field and a variable-length field, the number of data bytes in the variable-length field being a function of the number of active channels; and sending the packet of data.

Abstract: Methods and systems are provided for orientation of multicomponent geophones, for rotating traces, and for correcting polarity differences between traces. According to an example embodiment, a receiver orientation angle is assigned, based on a determination of an angle between one or more horizontal components and one or more sources.

Abstract: A computer system and method of operating the same to apply overburden corrections to seismic signals prior to amplitude-versus-offset (AVO) analysis is disclosed. The system and method retrieve common midpoint gathers of the seismic signals, and generate analytical, or complex, AVO intercept and AVO slope traces therefrom, effectively stacking the traces in each gather. Over a sliding time window of the stacks, the computer system generates p-measure standard deviation and correlation statistics, preferably using a p-measure value less than one. The AVO intercept and AVO slope traces are then modified, at each depth point of interest corresponding to a time window placement, according to the relationship between the p-measure statistics and the desired statistics for the background distribution.

Abstract: An apparatus and method for removing the distortion in marine seismic data resulting from the motion of the ship. The ship trails one or more seismic sources and receivers and moves forward at a known velocity. The seismic sources emit seismic waves that travel through the water and reflect off interfaces between rock formations below the ocean floor. The motion of the sources and receivers introduces distortion in the recorded seismic data that can be modeled using Doppler theory. The data preferably is corrected for source motion independently from the correction for receiver motion. The seismic data is first corrected for receiver motion and then for source motion. The technique for correcting for source motion includes correlating the receiver-corrected data with a reference sweep signal, performing an F-K transform, performing an inverse F-K transform on a selected subset of the F-K transformed data, and computing appropriate correction filters for the data resulting from the inverse F-K transform.

Abstract: A method for inverting a seismic signal, wherein an input seismic signal is represented as an input vector i(t) of length m+n-1, an output seismic signal is represented as an output vector o(t) of length m, and a finite impulse response filter is represented as a solution vector u(t) of length n, satisfying a convolutional equation i(t)Xu(t)=o(t). An m.times.n Toeplitz matrix T(t,.tau.) corresponding to i(t) is calculated, satisfying a matrix equation T(t,.tau.).multidot.u(t)=o(t). Both sides of the matrix equation are transformed to the frequency domain, to generate a transformed equation. Both sides of the transformed equation are spectrally pruned, to generate a pruned equation. The pruned equation is then solved.

Abstract: A seismic sensor pod is provided for coupling to a seismic cable and establishing a substantially water tight connection between the seismic cable and a seismic sensor. The pod includes a housing for holding the seismic sensor. The forward section of the housing includes a substantially sealed chamber. One or more conductors from the seismic cable are cut and the cut ends are projected into the chamber. Electrical connection between the cut ends of the conductors and the seismic sensor is established by a connector member. The pod provides a water resistant pathway between the conductors of the seismic cable and the seismic sensor, and a streamlined housing to hold the seismic sensor.

Abstract: A method for recording seismic data in deep water. A plurality of seismic data recorders are attached to a wire stored on a seismic vessel. A free end of the wire is deployed into the water, and the recorders are attached at selected positions along the wire. The wire and recorders are lowered into the water as the vessel moves to control the recorder deployment. The wire controls recorder location and establishes the recorder spacing interval. After the recorders are operated to record seismic data, the wire and attached recorders can be retrieved to the water surface. The recorders can be detached from the wire to facilitate storage and data retrieval from each recorder.

Abstract: A method for determining water bottom reflectivities whereby pressure signals and velocity signals are combined to generate combined signals having signal components representing downwardly-travelling energy substantially removed. The pressure and velocity signals correspond to seismic waves generated at source locations n in a water layer and detected by co-located pressure and velocity receivers at receiver locations m in the water layer. The combined signals correspond to each pairing of source location n and receiver location m. The combined signals are transformed from the time domain to the frequency domain, generating transformed signals. A source peg-leg term and a receiver peg-leg term is calculated for each transformed signal, generating filtered signals. An optimization algorithm is applied to the filtered signals, using the corresponding source and receiver peg-leg terms to determine the water bottom reflectivity values R.sub.n and R.sub.

Abstract: A technique and a system provide control and monitoring of devices external to a marine seismic streamer by segmenting the conductor to which the external devices are coupled. The module which connects sections of the seismic data telemetry cable is modified to include a switch. The switch is controlled by a command signal on the seismic data telemetry cable to segment the twisted pair bus into a plurality of dedicated busses, each dedicated to a subset of the external devices, such as one or two such devices. In this way, the external devices can be communicated with in parallel, rather than in series as in conventional systems.

Abstract: An apparatus and method are provided for detecting buries objects, geological formations or sediment properties by transmitting an acoustic signal and receiving a scattered signal. An acoustic source and an array of receivers are used to correlate the scattered signal with the transmitted signal.

Abstract: A method and computer system for deriving and applying normal moveout corrections to seismic survey traces is disclosed. In each common midpoint (CMP) gather, a stacking velocity function of travel time is first determined for near-offset traces. For each reflective event, a time window about a depth point is selected. Time anisotropy and velocity anisotropy values are then determined for the depth point, for example by way of a semblance analysis applied to envelopes of the traces over the full offset range. Normal moveout corrections are then determined by a weighted sum expression of travel time (zero-offset time plus moveout correction) The weighted sum adds a first travel time expression corresponding to a Dix equation expression with a second travel time expression corresponding to a skewed hyperbolic expression that includes the time and velocity anisotropy values, with the weighting dependent upon the offset of the particular trace.

Abstract: The present invention enables both deep marine seismic surveys and site seismic surveys to be performed simultaneously. A survey vessel tows a first seismic array (6, 16, 20) for a deep survey and a second seismic array (6, 16, 20) for the site survey. The arrays are operationally distinct but may share common physical components.

Abstract: A method for determining ocean bottom reflectivities from dual sensor seismic data, whereby a first time windowed pressure signal and a first windowed velocity signal are summed to generate a first summed signal, and a second time windowed pressure signal and a second time windowed velocity signal are summed to generate a second summed signal. The first summed signal and the second summed signal are transformed from the time domain to the frequency domain to generate a first transformed sum and a second transformed sum, respectively. A value R for said ocean bottom reflectivity is selected and used to calculate an inverse Backus filter (1+Rz).sup.2, where Z is the Z-transform of the two-way travel time delay filter. The first transformed sum and the second transformed sum are multiplied by the inverse Backus filter to generate a first filtered sum and a second filtered sum, respectively. A cross spectrum is calculated from the first filtered sum and the second filtered sum to generate a trial cross spectrum.

Abstract: A method for generating an unaliased 3-D DMO operator using two dimensional sampling theory to the spatial traverse of the operator as well as to the temporal axis. First a continuous DMO operator is generated along the line segment connecting a source and a receiver directed at an arbitrary azimuth relative to a biaxial output grid. The operator is discretized at spaced-apart sample points along the DMO aperture segment, the spacing being equal to or less than the output grid dimensions. A exponentially tapered sinc filter function is applied to the samples which are then interpolated onto the output grid.

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: A method of suppression of burst coherent noise in seismic data is provided comprising (a) comparing a threshold amplitude characteristic acceptance value for a time window of a reference trace to an amplitude characteristic of a test trace of a set of traces within the window and; (b) applying a non-zero scalar to the test trace in the time window if an amplitude of the test trace within the time window is not within the threshold amplitude characteristic acceptance value.