arXiv subjects

Andrey Bakulin

Publications and source records attributed to Andrey Bakulin.

3 recordsLinked to original sources

arXiv2026

Broadband Multi-Aperture Passive Scholte-Wave Imaging Using Seabed Distributed Acoustic Sensing

Shallow-water ocean forcing provides strong broadband passive Scholte-wave illumination along a seabed distributed acoustic sensing cable on the Texas Gulf Coast. We exploit this illumination through direct processing of the uncorrelated wavefield, long-duration frequency-wavenumber stacking, and a multi-aperture strategy that preserves high-frequency spatial localization while resolving low-frequency modes. Constant-wavenumber slices enable spatially consistent multimode tracking across successive array centers. The resulting dispersion spans approximately 0.3-4.5 Hz and supports 400 one-dimensional inversions along a 51-km cable segment. These profiles form a pseudo-2D shear-wave velocity model extending from the near seafloor to approximately 2 km depth. Broad shallow low-velocity intervals are consistent with softer incised-valley fill within stiffer Pleistocene deposits. The results demonstrate that existing seabed fiber infrastructure, when coupled with strong shallow-water passive illumination, can deliver broadband regional shear-wave imaging, while higher-frequency active sources remain necessary to resolve the uppermost several meters.

physics.geo-ph↗

arXiv2026

Phase variance as a seismic quality-control attribute

Seismic wavefields recorded on land are strongly distorted by near-surface heterogeneity, introducing trace-specific, frequency-dependent phase perturbations that persist even after advanced time processing. Conventional surface-consistent deconvolution targets long- to mid-wavelength phase variability through overdetermination, but cannot correct localized, non-surface-consistent distortions, and its effectiveness degrades when such effects dominate, as is often the case for point-receiver data. Additionally, conventional workflows provide no direct, quantitative measure of phase reliability; phase quality is assessed only indirectly through amplitude behavior or visual inspection, leaving residual phase disorder largely undiagnosed. We introduce phase variance as a seismic quality-control attribute by treating seismic phases as circular random variables and analyzing local trace ensembles using circular statistics. This data-driven measure quantifies localized phase dispersion without phase unwrapping, enabling analysis of local phase trends without global assumptions or wavelet models. Phase variance is computed automatically and provides frequency-by-frequency classification from coherent signal to fully randomized, noise-dominated phase. Synthetic tests confirm that phase variance reliably captures imposed phase perturbations and their frequency dependence. Application to field prestack land data shows that conventional processing reduces phase variability primarily in the low-to-intermediate frequency range and struggles within the noise cone, while the highest and lowest frequencies show little improvement. Phase variance operates automatically over the full prestack volume, frequency by frequency, providing a consistent, human-independent metric for defining effective bandwidth and supporting phase-sensitive workflows such as AVO, migration, and full-waveform inversion.

physics.geo-ph↗

arXiv2023

A self-supervised scheme for ground roll suppression

In recent years, self-supervised procedures have advanced the field of seismic noise attenuation, due to not requiring a massive amount of clean labeled data in the training stage, an unobtainable requirement for seismic data. However, current self-supervised methods usually suppress simple noise types, such as random and trace-wise noise, instead of the complicated, aliased ground roll. Here, we propose an adaptation of a self-supervised procedure, namely, blind-fan networks, to remove aliased ground roll within seismic shot gathers without any requirement for clean data. The self-supervised denoising procedure is implemented by designing a noise mask with a predefined direction to avoid the coherency of the ground roll being learned by the network while predicting one pixel's value. Numerical experiments on synthetic and field seismic data demonstrate that our method can effectively attenuate aliased ground roll.

physics.geo-ph↗