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Seismic Data Regularization and Imaging Based on Compressive Sensing and Sparse Optimization
Published in C.H. Chen, Compressive Sensing of Earth Observations, 2017
Seismic exploration method is a crucial method to explore oil/gas, coal, and other resources in the underground. Geophones that are arranged at the earth’s surface or in wells can record vibrations of the earth. Data recorded by geophones can be used to extract velocity information from the underground medium after a series of processing flow. In order to reconstruct the structure of the earth correctly, seismic acquisition should satisfy the Nyquist/Shannon sampling theorem not only in the time domain but also in the space domain. Generally, the sampling process in the time domain can fulfill the sampling theorem. However, sampling in the space domain often violates the sampling theorem due to the influence of obstacles, rivers, bad traces, noise, acquisition aperture, topography, and acquisition costs. Seismic data that violate the Nyquist/Shannon sampling theorem may bring harmful aliases and deteriorate the results of migration (Liu and Sacchi 2004), multiple elimination (Naghizadeh 2009), denoising (Soubaras 2004), and amplitude versus offset (AVO) analysis (Liu 2004; Sacchi and Liu 2005; Naghizadeh and Sacchi 2010). In order to remove the influences of subsampled data, the seismic regularization/interpolation/reconstruction/restoration technique is a key step to provide reliable data from the subsampled data. Thus, seismic interpolation is a crucial research direction in exploration seismology (Wang et al. 2011).
Reflection and transmission of three-dimensional plane wave at an imperfectly bonded interface between two distinct rotating functionally graded triclinic media
Published in Waves in Random and Complex Media, 2023
Akanksha Srivastava, Abhishek Kumar Singh, Amares Chattopadhyay
Seismic surveys of reflection and transmission in a solid-solid model are quite an interesting topic for engineers, scientists and scholars and all the outcomes have aggressively contributed to the disciplines of geophysics, fracture mechanics, seismology, civil and construction engineering, etc., which serve as a motivation for the present study. The presence of a discontinuity in the material properties generally produces a profound influence on the phenomena of waves propagating through the medium. When waves come into contact with new mediums, obstacles, or other waves, they behave in certain characteristic ways. Waves exhibit several fundamental phenomena, such as reflection, transmission and diffraction. The fundamental equations for reflection and transmission of plane elastic waves at welded contact were initially derived by Knott [1]. This fundamental work was subsequently explained in some famous books authored by Ewing et al. [2–5]. In the real world, the existence of reflection and transmission phenomena are proven and considered useful for the exploration of the earth's internal structure as well as the exploration of valuable materials buried inside the earth, for example, metals, minerals, petroleum and hydrocarbons. For this purpose, AVO analysis is useful, and this technique is based on the relationship between amplitude ratios and angle of incidence. This analysis also aids in estimating P and S-wave velocities as well as infers the petro-physical properties of the formation, which is useful in determining the source location. Ruger [6] studied the reflection coefficients and azimuthal AVO analysis of anisotropic modeling.