Zhdanov, M.S. and Tjan, T., 1994. Migration by analytic continuation through a variable background medium. Journal of Seismic Exploration, 3: 283-297. Conventional migration of wavefields is based on depth extrapolation of the upgoing field in reverse time. This extrapolation provides us with a means to determine the positions of reflectors and diffraction points and, therefore, to produce an i...

Inverse scattering series is the only nonlinear, direct inversion method for the multidimensional, acoustic or elastic equation. Recently developed techniques for inverse problems based on the inverse scattering series [Weglein et al., Geophys., 62 (1997), pp. 1975–1989; Top. Rev. Inverse Problems, 19 (2003), pp. R27–R83] were shown to require two mappings, one associating nonperturbative descr...

The seismic refraction technique provides a simplified characterization of relatively large volumes of the subsurface in 2-dimensional (distance and depth) profiles. Compression wave (p-wave) velocities, the typical measured geologic material parameter, are a function of the moduli of the various unsaturated material masses in the subsurface profile. In saturated media, p-wave velocities are in...

Seismic tomography is a technique to determine the material properties of the Earth’s subsurface based on the observation of seismograms. This can be stated as a PDE-constrained optimization problem governed by the elastic wave equation. We present a semismooth Newton-PCG method with a trust-region globalization for full-waveform seismic inversion that uses a MoreauYosida regularization to hand...

The purpose of this work is to present and analyze the results of numerical simulations related to the application of three different mathematical models in the acoustic seismic wave propagation in which only compressional waves (P-waves) are contemplated. And present the results of an investigation about how these wave equation implementations can influence the amplitudes of a migrated section...

Seismic signal processing is an important task in geophysics sounding and represents a permanent challenge in petroleum exploration. Although seismograms could in principle give us a picture of a geological structure, they are very contaminated by spurious signals and the ground roll noise is a strongly undesired signal present in the seismograms – it does not carry physical information about t...

A sonobuoy field was deployed in the Marginal Ice Zone of the Fram Strait in June 2011 to study the spatial variability of ambient noise. High noise levels observed at 10-200 Hz are attributed to distant (1400 km range) seismic exploration. The noise levels decreased with range into the ice cover; the reduction is fitted by a spreading loss model with a frequency-dependent attenuation factor le...

In this work, we present an efficient parallel implementation of a depth migration RTM (Reverse Time Migration) method to obtain a seismic image. This migration technique is based on the parallel solution of the acoustic wave propagation in 2D using a finite difference scheme. We have implemented a domain decomposition on the geological section and exploit an efficient asynchronous communicatio...

Accurate interpretation of seismic traveltimes and amplitudes in the exploration and global scales is complicated by the band-limited nature of seismic data. We discovered a stochastic method to reduce a seismic waveform into a most probable constituent spike train. Model waveforms were constructed from a set of candidate spike trains convolved with a source wavelet estimate. For each model wav...

Modern underground coal mining requires certainty about geological faults and other structural features for safety reasons. Even a fault with a throw of a few metres can create safety issues and lead to costly delays in mine production. To ensure there are no unwelcome surprises concerning seam conditions during mining, seismic reflection surveys have been widely used by Australian coal mines, ...