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Kazei, V.V. (author), Ponomarenko, A.V. (author), Troyan, V.N. (author), Kashtan, B.M. (author), Mulder, W.A. (author)Full waveform inversion suffers from local minima, due to a lack of low frequencies in the data. A reflector below the zone of interest may, however, help in recovering the longwavelength components of a velocity perturbation, as demonstrated in a paper by Mora. With the Born approximation for the perturbation in a reference model consisting of...conference paper 2012
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Ponomarenko, A.V. (author), Kashtan, B.M. (author), Troyan, V.N. (author), Mulder, W.A. (author)Surface waves can be used to obtain a nearsurface shear wave profile. The inverse problem is usually solved for the locally 1D problem of a set of homogeneous horizontal elastic layers. The output is a set of shear velocity values for each layer in the profile. Pwave velocity profile can be estimated if higher modes and Pguided waves are...conference paper 2013
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Ponomarenko, A.V. (author), Kashtan, B.M. (author), Troyan, V.N. (author), Mulder, W.A. (author)Recently, we proposed an analytical approach to invert for a smoothly varying nearsurface Pwave velocity profile that has a squared slowness linearly decreasing with depth. The exact solution for such a velocity profile in the acoustic approximation can be expressed in terms of Airy functions and leads to a dispersion equation. The method was...conference paper 2013
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Ponomarenko, A.V. (author), Kashtan, B.M. (author), Troyan, V.N. (author), Mulder, W.A. (author)We inverted seismic field data for a continuous, laterally invariant Pwave velocity profile. Instead of the usual approach that involves horizontal layers with piecewise constant densities and velocities, we consider models of one or two layers with a constant gradient of the squared slowness above a homogeneous halfspace. With a single layer...conference paper 2015
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Ponomarenko, A. V. (author), Kashtan, B. M. (author), Troyan, V. N. (author), Mulder, W.A. (author)Surface waves are often used to estimate a nearsurface shearvelocity profile. The inverse problem is solved for the locally onedimensional problem of a set of homogeneous horizontal elastic layers. The result is a set of shear velocities, one for each layer. To obtain a Pwave velocity profile, the Pguided waves should be included in the...journal article 2017