An autonomous sensor node for undersea seismic surveying is formed as a sphere with density similar to sea water in order to minimize effects of noise. The node is capable of measuring both seismic pressure waves and water-borne particle velocity in three dimensions. The node floats above the seafloor to greatly decrease the impact of shear wave noise contamination generated by seabed waves. The node is attached to an anchor resting on the seabed by a tether. The tether is configured to prevent transfer of any tensile forces caused by shear waves in the seabed stratum from the anchor to the node. The tether may have a varying density along its length to entirely attenuate any force transfer from the seafloor.

A method includes receiving seismic data of a seismic survey; defining a two-dimensional domain in dimensions x and y; identifying a target trace (S, R) of the seismic survey where S represents a source at (x.sub.s, y.sub.s) and where R represents a receiver at (X.sub.R, y.sub.R); defining with respect to the two-dimensional domain, a source trace (S, X.sub.1) as a primary trace, a receiver trace (R, X.sub.2) as a primary trace, and a generator trace (X.sub.1, X.sub.2) as associated with an interbed multiple generator; convolving the primary traces and crosscorrelating with the generator trace for a plurality of different (X.sub.1, X.sub.2) pairs where each of the plurality of (X.sub.1, X.sub.2) pairs defines a line segment where the line segments are substantially parallel to one another; and, based at least in part on the convolving the primary traces and crosscorrelating with the generator trace, generating seismic data with attenuated multiple energy.

A method of at least partially deghosting recorded seismic s-waves, wherein recorded seismic data is provided, wherein the recorded seismic data has been recorded at a receiver located beneath the Earth's surface, and wherein the recorded seismic data includes s-wave data. The method may include the steps of finding a model of the Earth's crust for use in deghosting the recorded seismic data using the s-wave data, wherein the model includes at least one region and wherein the model includes the Earth's surface and the location of the receiver, using the model to find a deghosting operator that, when applied to the s-wave data, at least partially deghosts the s-wave data, and applying the deghosting operator to the s-wave data to at least partially deghost the s-wave data.

Various implementations directed to quality control and preconditioning of seismic data are provided. In one implementation, a method may include receiving particle motion data from particle motion sensors disposed on seismic streamers. The method may also include performing quality control (QC) processing on the particle motion data. The method may further include performing preconditioning processing on the QC-processed particle motion data. The method may additionally include attenuating noise in the preconditioning-processed particle motion data.

Systems, computer readable, and methods concern receiving seismic data representing a subsurface volume. The method also includes determining, for the seismic data, analysis coordinates as a function of time. One or more of the analysis coordinates may vary in position over time. The method includes performing at least one of an interpolation or regularization process on the seismic data based at least partially on the analysis coordinates. The method also includes outputting a result of the at least one of the interpolation or regularization process.

A method for estimating noise in particle motion seismic recordings and upgoing (deghosted) and downgoing components of ecorded wavefields includes inputting pressure related and particle motion related seismic signals. A sparsity promoting transformation is applied to the input seismic signals. A matrix à and column vector {tilde over (b)} are constructed according to the expression:

[00001]$\begin{array}{ccc}\tilde{A}=\left(\begin{array}{ccc}I& I& 0\\ I& -I& \lambda I\end{array}\right)& \tilde{x}=\left(\begin{array}{c}d\\ u\\ n\end{array}\right)& \tilde{b}=\left(\begin{array}{c}{A}^{-1}p\\ A^{-1}z\end{array}\right),\end{array}$

wherein d represents a down-going seismic wavefield, u represents an up-going seismic wavefield, n represents the noise and λ represents a user-chosen scalar to adjust emphasis of the noise. A constrained minimization is solved according to the expression

[00002]$\begin{array}{ccc}\tilde{x}=\arg \min \mu {.Math.\tilde{x}.Math.}_1+\frac{1}{2}{.Math.\tilde{x}.Math.}_2^2& \mathrm{st}& \tilde{A}\tilde{x}\end{array}=\tilde{b}$

for {tilde over (x)}; wherein μ represents a us

Computing device, computer instructions and method for processing input seismic data d. The method includes receiving the input seismic data d recorded in a first domain by seismic receivers that are towed in water, the input seismic data d including pressure data and/or and particle motion data; generating a model p in a second domain to describe the input data d; processing the model p to generate an output particle motion dataset; and generating an image of the surveyed subsurface based on the output particle motion dataset.

A method of performing notch compensation and a system to perform notch compensation for a first seismic streamer are described. The method includes disposing the first seismic streamer at a first depth, where the seismic streamer includes a first set of sensors to receive reflections resulting from a seismic source, the reflections indicating a notch at a frequency. The method also includes disposing a second seismic streamer at a second depth, the second depth being less than the first depth and the second seismic streamer including a second set of sensors to receive reflections resulting from the seismic source. The method further includes processing the reflections received by the first set of sensors and the second set of sensors together to derive the match filter, and applying the match filter to the reflections received by the first set of sensors of the first seismic streamer to compensate for the notch.

A method for estimating a far field seismic energy source signature includes using detected near field seismic signals corresponding to actuation of each one of a plurality of seismic energy sources in an array of seismic energy sources. The near field seismic signals are detected at two spaced apart locations in the near field of each seismic energy source, the at least two spaced apart locations being arranged such that a direction of propagation of the detected near field seismic signals is determinable from the detected near field signals. A notional source signature for each seismic energy source and a notional ghost for each seismic energy source using the detected near field seismic signals. A far field signature is determined for the plurality of seismic energy sources using the determined notional source signature and notional ghost signature from each seismic energy source.

An apparatus obtains measurements from a seismic sensor, wherein the seismic measurements include a set of seismic waves having at least a subset of seismic multiples and a machine-readable medium having program code executable by a processor to cause the apparatus to determine seismic measurements of the seismic waves, fit reflectivity model based on a set of reflectivity models using a nonlinear scheme to the seismic measurements, and identify a subset of the seismic measurements corresponding to the subset of seismic multiples. The apparatus also includes program code to cause the apparatus to generate a set of reduced-noise seismic measurements based on attenuation of the subset of the seismic measurements.