A5047858125- Seismic Imaging and Inversion Techniques
- Seismic Waves and Analysis
- Hydraulic Fracturing and Reservoir Analysis
- Seismology and Earthquake Studies
- Underwater Acoustics Research
- Geophysics and Sensor Technology
- Image and Signal Denoising Methods
- High-pressure geophysics and materials
- Numerical methods in engineering
- Advanced X-ray and CT Imaging
- Thermoelastic and Magnetoelastic Phenomena
- Numerical methods for differential equations
- Earthquake Detection and Analysis
- Nonlinear Waves and Solitons
- Medical Imaging Techniques and Applications
- Geophysical Methods and Applications
- Geophysical and Geoelectrical Methods
Pennsylvania State University
2018-2024
Chevron (United States)
2023-2024
Rice University
2014-2016
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...
Abstract Quantifying the attenuation of seismic waves propagating in Earth interior is critical to study subsurface structure. Previous studies have proposed fractional anelastic wave equations model frequency‐independent Q propagation. Such involve derivatives that pose computational challenges for numerical schemes terms accuracy and efficiency when dealing with heterogeneous media. To tackle these challenges, here we derive a new viscoacoustic equation, where power Laplacian operators are...
We have formulated the Fréchet kernel computation using adjoint-state method based on a fractional viscoacoustic wave equation. first numerically prove that 1/2- and 3/2-order Laplacian operators are self-adjoint. Using this property, we find adjoint propagator preserves dispersion compensates amplitude, whereas time-reversed behaves identically to forward with same dissipation characters. Without introducing rheological mechanisms, formulation adopts an explicit [Formula: see text]...
Recent progress on fractional modeling enables incorporatingseismic attenuation into wavefield simulation in an accurate and effcient way. But its inverse problem, i.e., the multiparameter viscoacoustic full waveform inversion (FWI), still suffers from various issues, especially crosstalk between velocity attenuation. In this study, we integrate Hessian information via Newton-CG framework develop FWI algorithm. It significantly mitigates problems sheds light upon simultaneous for both Q...
Seismic attenuation poses challenges to velocity model building from acoustic/elastic full-waveform inversion (FWI). In particular, when constructing the FWI gradient for inversion, recent studies have indicated that high-attenuation structure could distort by damping amplitudes and shifting kinematic phases, resulting in an imbalanced update thus unreliable model. These Q effects are particularly significant reflection acquisition geometry due “double-damping” issue. Here, we develop a...
Seismic waves propagating in the Earth media exhibit an approximate constant-Q behavior seismic frequency bands and can be parameterized by independent Q (constant-Q) model. The model that is derived mathematically lacks a physical basis. In this study, we propose fractal mechanical network with alternating springs dashpots to provide mathematical motivation. With this, derive new time domain viscoacoustic wave equation where fractional Laplacian power terms are of heterogeneity. This...
Surface wave tomography routinely uses empirically scaled density model in the inversion of dispersion curves for shear speeds crust and uppermost mantle. An improperly selected empirical scaling relationship between speed can lead to unrealistic models beneath certain tectonic formations such as sedimentary basins. Taking Sichuan basin east Tibetan plateau an example, we investigate differences profiles calculated from four methods their effects on Rayleigh phase velocities. Analytical...
SUMMARY Seismic attenuation (quantified by the quality factor Q) has a significant impact on seismic waveforms, especially in fluid-saturated rocks. This dissipative process can be phenomenologically represented viscoelastic models. Previous seismological studies show that Q value of Earth media exhibits nearly frequency-independent behaviour (often referred to as constant-Q literature) frequency range. Such described mathematical Kjartansson model, which lacks physical representation sense....
To accurately simulate wave propagation in the earth, dispersion and dissipation caused by attenuation should be taken into account during wavefield extrapolation. In this study, we derive a spatial-independent-order decoupled fractional Laplacian (DFL) viscoelastic equation based on relation of constant-Q model. The proposed DFL similar to equations show anelastic effects. addition, formulation has superiority that power orders operators are constant. For numerical simulations heterogeneous...
Continuous seismic monitoring for quantifying CO 2 plume migration and detection of any potential leakages in the subsurface is essential security long-term anthropogenic carbon dioxide geologic storage. Traditional time-lapse full-waveform inversion (TLFWI) methods aim to map distribution by estimating velocity changes, but recent studies find that -induced attenuation an important complement tracking plumes even saturation. We have developed a novel data-assimilated TLFWI method construct...
Accurate seismic attenuation models of subsurface structures not only enhance subsequent migration processes by improving fidelity, resolution, and facilitating amplitude-compliant angle gather generation but also provide valuable constraints on physical properties. Leveraging full-wavefield information, multiparameter viscoacoustic full-waveform inversion ( Q-FWI) simultaneously estimates velocity Q) models. However, a major challenge in Q-FWI is the contamination crosstalk artifacts, where...
Incorporating the seismic attenuation into waveform inversion framework could not only improve accuracy of velocity model but also provide an additional Q model. Recently, we proposed a viscoacoustic wave equation assisted by fractional Laplacian operators to accurately propagation in heterogeneous attenuating media with computational efficiency. The explicit presence as coefficient this suggests potential conveniently develop its full scheme. In study, utilize adjoint-state method formulate...