Reverse time migration (RTM) for attenuating media should take amplitude compensation and phase correction into consideration. However, attenuation during seismic propagation suffers from numerical instability because of the boosted high-frequency ambient noise. We have developed a novel adaptive stabilization method [Formula: see text]-compensated RTM ([Formula: text]-RTM), which exhibits superior properties variance text] dependence over conventional low-pass filtering-based method. derive...

Recently, a decoupled fractional Laplacian viscoacoustic wave equation has been developed based on the constant-[Formula: see text] model to describe propagation in heterogeneous media. We have two efficient modeling schemes solve equation. Both can cope with spatial variable-order Laplacians conveniently, and thus are applicable for fast Fourier transform, spectral accuracy space. The first scheme solves modified constant-order instead of Laplacians. Due separate discretization space time,...

Abstract Seismic velocity and attenuation anisotropy are ubiquitous in the crust upper mantle, significantly modulating characteristics of seismic wave propagation Earth's interior. Accurate modeling is essential for understanding interior as well constructing global region‐scale full waveform tomography. Here, we derive a decoupled fractional Laplacian (DFL) viscoelastic equation to characterize frequency‐independent Q behavior vertical transversely isotropic (VTI) media. We verify accuracy...

Bayesian linearized inversion (BLI) stands out as an exceptional stochastic method in the realms of geophysics and remote sensing. It excels estimating results assessing their uncertainty with remarkable efficiency. However, one challenges faced by BLI lies its core matrix. To surmount this limitation, innovative dimension reduction strategy is proposed based on discrete cosine transform (DCT), thus formulating a rapid approach termed DCT-BLI. Within method, DCT-based effectively compresses...

High-resolution prestack inversion combining the well-logging and seismic data is a significant geophysical task can be achieved by two kinds of stochastic approaches, geostatistical (GSI) Bayesian linearized (BLI). Nevertheless, existing GSI restricted heavy iteration calculation. Although BLI avoid this issue, it suffers from large core matrix inverse. A fast multi-Gaussian (FMG_INV) proposed herein to achieve well-log combined with higher efficiency than BLI. FMG_INV derived BLI, which...

Clustering is one of the most useful tools for high-dimensional analysis, e.g., microarray data. It becomes challenging in presence a large number noise variables, which may mask underlying clustering structures. Therefore, removal through variable selection necessary. One effective way regularization simultaneous parameter estimation and model-based clustering. However, existing methods focus on regularizing mean parameters representing centers clusters, ignoring dependencies among...

To analyse the type and location of defects in HyFlex CM instruments after clinical use a graduate endodontic programme to examine impact on their metallurgical properties.A total 468 discarded from were collected three teeth. The incidence instrument analysed. lateral surfaces defect examined by scanning electron microscopy. New clinically used differential calorimetry (DSC) x-ray diffraction (XRD). Vickers hardness was measured with 200-g load near flutes for new axially sectioned...

Due to the energy attenuation and phase distortion of seismic waves propagating in viscous media, it is difficult obtain high resolution amplitude preserved migration images without compensating effects. In this paper, we provide a reverse time (RTM) scheme based on viscoacoustic wave equation with fractional Laplacian operators compensate First, develop high-efficiency method for simulating propagation equation. Since independent number different Q values, numerical simulation examples show...

Simultaneous-source acquisition, breaking the limit of conventional seismic is a rapidly evolving research field, due to its advantage in reducing survey time and improving data quality. The benefits simultaneous-source acquisition are compromised by intense blending interference. Separating blended record into group individual records, known as "deblending" one most popular solution problem. However, records often corrupted random noise, which causes difficulties separation. In an iterative...

In recent years, sparse representation is seeing increasing application to fundamental signal and image-processing tasks. representation, a can be expressed as linear combination of dictionary (atom signals) coefficients. Dictionary learning has critical role in obtaining state-of-the-art representation. A good should capture the representative features data. The whole used training patches learn dictionary. However, this approach suffers from high computational costs, especially for 3D...

The lack of low-frequency signals in seismic data makes the full-waveform inversion (FWI) procedure easily fall into local minima leading to unreliable results. To reconstruct missing more accurately and effectively, we have developed a data-driven recovery method based on deep learning from high-frequency signals. In our method, develop idea using basic patch build mapping recovery. Energy balancing patches are used prepare high- for training convolutional neural network (CNN) establish...

Frequency-dependent amplitude absorption and phase velocity dispersion are typically linked by the causality-imposed Kramers–Kronig relations, which inevitably degrade quality of seismic data. Seismic attenuation compensation is an important processing approach for enhancing signal resolution fidelity, can be performed on either pre-stack or post-stack data so as to mitigate effects resulting from intrinsic anelasticity subsurface media. Inversion-based with L1 norm constraint, enlightened...

The traditional high-order staggered-grid finite-difference (SGFD) method has accuracy in space, but only the second-order time, which makes SGFD suffer from a large temporal dispersion error during long-distance wave propagation. This paper develops fourth- and sixth-order spatial arbitrary evenorder schemes to model isotropic elastic have smaller than scheme, thus allow larger time steps attain similar accuracy. developed are applied simulate quasi-stress–velocity equation (QWE) that is...

Simultaneous-source method is usually adopted, as one of the most efficient ways, to reduce computation cost full waveform inversion (FWI). Unfortunately, this facing with problem crosstalk noise, degrading quality results. To avoid problem, we propose an algorithm time–frequency hybrid-domain simultaneous-source FWI based on time-domain finite difference phase sensitive detection method. The harmonic sine functions different frequencies are used wavelet signals for sources within super...

Accurate estimation of source wavelet is crucial in a successful full-waveform inversion (FWI); however, it cannot be guaranteed the case real seismic data. We have developed time-domain source-independent elastic FWI using convolution-based objective function that was originally for acoustic FWI. applied new time window on reference traces to suppress noises induced by convolution and crosscorrelation operations. Also, we adopted [Formula: see text]-, Huber-, hybrid-norm functions improve...

Reverse time migration (RTM) in attenuating media should take absorption and dispersion effects into consideration. The latest proposed viscoacoustic wave equation with decoupled fractional Laplacians facilitates separate amplitude compensation phase correction [Formula: see text]-compensated RTM ([Formula: text]-RTM). However, intensive computation enormous storage requirements of text]-RTM prevent it from being extended practical application, especially for large-scale 2D or 3D cases....

Bayesian statistical inversion can integrate diverse datasets to infer the posterior probability distributions of subsurface elastic properties. However, certain existing methods may suffer from two issues in practical applications, namely spatial discontinuities and uncertainty caused by low-quality seismic traces. These limitations are evident prestack since some traces angle gathers be missing or low-quality. We propose a method constrained reflection features alleviate these issues....

Simultaneous source acquisition, which allows a temporal overlap between shot records, has significant advantages to improve data quality (e.g., denser shooting) and reduce acquisition cost efficient wide-azimuth shooting). We have developed novel shot-domain deblending approach for simultaneous shooting survey based on an inversion scheme. The inverse problem is formulated by introducing two convolution operators that can respectively destruct the signal interference solved...

Efficient modeling schemes currently exist to handle the spatially variable-order fractional Laplacians in Laplacian viscoacoustic wave equation. The simplest approach is change into a linear combination of several constant fractional-order Laplacians. We generalize scheme variable viscoelastic equation and develop an almost-equivalent Our avoids simulation error introduced by directly averaging varying order; thus, our simulates seismic propagation media with sharp [Formula: see text]...

The proximal splitting algorithm, which reduces complex convex optimization problems into a series of smaller subproblems and spreads the projection operator onto set proximity function, has recently been introduced in area signal processing. Following framework, we propose novel three-operator (TOPS) algorithm for 3-D seismic data reconstruction with both singular value decomposition (SVD)-based low-rank constraint curvelet-domain sparsity constraint. Compared well-known forward-backward...