Seismic trace

Of course the typical seismic trace has many hundreds of reflections in it, all the way down from the surface to the deepest times measured. These days, engineers and geologists prefer to see the seismic in terms of the acoustic impedance rather than reflection data and this can be obtained by inversion from the seismic volume. Aseismic volume is made up of hundreds of thousands of traces. 

Taner M.T., Koehler F., Sheriff R.E., 1979. Complex seismic trace analysis. Geophysics 44 1041 - 1063... 

Natural variability between boreholes or trial pits, even with the best methods of interpretation (e.g. interpolation using seismic traces) will still leave uncertainty here. Indeed, the action of the sea between the design survey and construction can actually affect shallow underlying material. For example, the motion of the beach material under wave action can abrade clay or soft chalk platforms underlying the beach surface. 

Seismk Monitoring of Volcanoes, Fig. 4 Seismic traces and corresponding spectrograms for the vertical components of seven seismic stations near Akutan Volcano, ctnresptmding to 10 min of data on April 22, 2014. A Tegiraial earthquake is visible clearly around 20 13... 

Seismic trace frequency attributes, such as instantaneous frequency [15], are widely used in seismic data analysis. The instantaneous frequency attribute is available in most standard seismic data analysis packages. 

A similar measure to the Gabor filter bank, Subsection 3.5, may be extracted using the volume reflection spectral (VRS) decomposition [16]. In this approach, the seismic traces are decomposed by a Chebychev polynomial, and the polynomial coefficients are used as spectral components, representing an attribute volume. An example for this is shown in Figure 11. 

A 3D seismic volume is represented by a cube S = S x,y,z) containing seismic amplitudes at each voxel position x,y,z), where x and y are positions in the two horizontal directions, measured in distance, and 2 is the position in the vertical dimension, measured in depth or two-way travel-time. The column S xq, yo, z) at position (xq, yo) is denoted a seismic trace. A seismic horizon is a piecewise continuous surface in 3D, consisting of positions 2 = g x, y) within the seismic volume. Throughout this work, seismic horizon segments are used as primitives for structural interpretation. Horizon interpretations are often placed on minimum, maximum or zero crossing events in the seismic cube, and are defined as piecewise continuous surfaces in 3D falling along these types of events. Minimum and maximum events in a seismic cube are commonly referred to as seismic extrema, and are chosen as the basis for the automated horizon interpretation presented in this paper. A set of seismic extrema can be described as a contour surface... 

The extrema cubes are generated using volume reflection spectral analysis technology [9, 10], where each seismic trace is locally reconstructed using the orthogonal basis defined by the Chebyshev polynomials. Thus, locally the seismic trace is represented as... 

The seismic wave form aroimd a seismic extremum can be described through a set of seismic attributes. The seismic attributes are obtained using reconstruction techniques of the seismic trace, such that the seismic signal is locally... 

Fig. 2. Reconstruction of a single trace from a seismic section. Image (a) shows the seismic section, with the seismic trace marked with white. The plots in (b) show the seismic trace (solid curve) and corresponding reconstructions (dashed curves). The number of attributes applied in the reconstructions increases from left to right.

Among these seismic attributes, those derived from the complex seismic trace analysis, developed in [41], have been extensively used in the industry for reservoir characterisation and monitoring. These attributes are derivatives of the basic seismic measurements, meaning that the use of complex trace analysis is simply a way to present and analyse a limited amount of information contained in the seismic trace. 

More recently, numerous case studies have demonstrated the value of wave shape classification using neural networks. With this method, the seismic trace is decomposed into components of amplitude and frequency information such as in VRS (Volume Reflection Spectrum) attributes [39]. 

Dynamic Texture Attributes. Dynamic texture attributes are generated from the original seismic cube. The volume reflection spectrum (VRS) attributes realize spectral analysis of the reflectivity response for each seismic trace [39]. Each trace is characterized in terms of its eigenvalue (spectral attribute) and the associated eigenvector (orthogonal, polynomial), to a > proximate the reflection amplitude along the trace in a least squares sense. For texture mapping a set of discrete spectral VRS coefficients is combined into a composite spectral representation. 

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