Application of the Multiaxial Perfectly Matched Layer to Near‐Surface Seismic Modeling with Rayleigh Waves

2011 ◽  
Author(s):  
Chong Zeng ◽  
Jianghai Xia ◽  
Richard Miller ◽  
Georgios Tsoflias
Keyword(s):  
Rayleigh Waves ◽  
Perfectly Matched Layer ◽  
Seismic Modeling ◽  
Near Surface

scholarly journals Application of the multiaxial perfectly matched layer (M-PML) to near-surface seismic modeling with Rayleigh waves

Geophysics ◽  
2011 ◽  
Vol 76 (3) ◽  
pp. T43-T52 ◽  
Author(s):  
Chong Zeng ◽  
Jianghai Xia ◽  
Richard D. Miller ◽  
Georgios P. Tsoflias
Keyword(s):  
Free Surface ◽  
Rayleigh Waves ◽  
Poisson’S Ratio ◽  
Perfectly Matched Layer ◽  
Poisson's Ratio ◽  
Seismic Modeling ◽  
Numerical Tests ◽  
Earth Models ◽  
Poisson's Ratios ◽  
Poisson’S Ratios

Perfectly matched layer (PML) absorbing boundaries are widely used to suppress spurious edge reflections in seismic modeling. When modeling Rayleigh waves with the existence of the free surface, the classical PML algorithm becomes unstable when the Poisson’s ratio of the medium is high. Numerical errors can accumulate exponentially and terminate the simulation due to computational overflows. Numerical tests show that the divergence speed of the classical PML has a nonlinear relationship with the Poisson’s ratio. Generally, the higher the Poisson’s ratio, the faster the classical PML diverges. The multiaxial PML (M-PML) attenuates the waves in PMLs using different damping profiles that are proportional to each other in orthogonal directions. The proportion coefficients of the damping profiles usually vary with the specific model settings. If they are set appropriately, the M-PML algorithm is stable for high Poisson’s ratio earth models. Through numerical tests of 40 models with Poisson’s ratios that varied from 0.10 to 0.49, we found that a constant proportion coefficient of 1.0 for the x- and z-directional damping profiles is sufficient to stabilize the M-PML for all 2D isotropic elastic cases. Wavefield simulations indicate that the instability of the classical PML is strongly related to the wave phenomena near the free surface. When applying the multiaxial technique only in the corners of the PML near the free surface, the original M-PML technique can be simplified without losing its stability. The simplified M-PML works efficiently for homogeneous and heterogeneous earth models with high Poisson’s ratios. The analysis in this paper is based on 2D finite difference modeling in the time domain that can easily be extended into the 3D domain with other numerical methods.

Surface-Wave Simulation for the Continuously Moving Seismic Sources

2021 ◽  
Author(s):  
Yuefeng Yan ◽  
Chengyu Sun ◽  
Tengfei Lin ◽  
Jiao Wang ◽  
Jidong Yang ◽  
...  
Keyword(s):  
Rayleigh Waves ◽  
Frequency Dispersion ◽  
Dispersion Curves ◽  
Velocity Estimation ◽  
Surface Velocity ◽  
Seismic Sources ◽  
Near Surface ◽  
Moving Source ◽  
Source Data ◽  
Doppler Effects

Abstract In exploration and earthquake seismology, most sources used in subsurface structure imaging and rock property estimation are fixed in certain positions. Continuously moving seismic sources, such as vehicles and the metro, are one kind of important passive sources in ambient noise research. Commonly, seismic data acquisition and processing for moving sources are based on the assumption of simple point passive sources, and the dispersion curve inversion is applied to constrain near-surface velocity. This workflow neglects the Doppler effects. Considering the continuously moving properties of the sources, we first derive the analytical solution for the Rayleigh waves excited by heavy vehicles and then analyze their Doppler effects and dispersion curves. We observe that the moving source data have the Doppler effect when compared with the changes in the frequency of the source intensity, but this effect does not affect the frequency dispersion of Rayleigh waves. The dispersion curves computed for moving source records are consistent with the analytical dispersion solutions, which provide a theoretical foundation for velocity estimation using moving source data.

Feasibility of determiningQof near‐surface materials from Rayleigh waves

2001 ◽  
Author(s):  
Jianghai Xia ◽  
Richard D. Miller ◽  
Choon B. Park ◽  
Julian Ivanov
Keyword(s):  
Rayleigh Waves ◽  
Near Surface ◽  
Surface Materials

Propagation of dispersed compressional and Rayleigh waves on the Texas coastal plain

Geophysics ◽  
1983 ◽  
Vol 48 (1) ◽  
pp. 27-35 ◽  
Author(s):  
Joseph Ebeniro ◽  
Clark R. Wilson ◽  
James Dorman
Keyword(s):  
Coastal Plain ◽  
Rayleigh Waves ◽  
Poisson Ratio ◽  
Normal Modes ◽  
Compressional Wave ◽  
Unconsolidated Sediments ◽  
Near Surface ◽  
Shallow Subsurface ◽  
Strong Surface ◽  
Group Velocities

During a refraction profile on the Texas coastal plain, a strong surface wave with predominant frequencies between 2 and 10 Hz and group velocities near 1.9 km/sec was observed to ranges as great as 64 km. This dispersed wave, with velocities near the compressional wave speed of near‐surface sediments, corresponds to the “leaky” compressional or PL wave. PL dispersion can be predicted from the theory of the normal modes of a layered liquid medium. Efficient propagation of the PL wave is related to the high Poisson ratio of the unconsolidated sediments in the shallow subsurface, and additional examples from the published literature show that the PL wave is commonly excited by shallow sources both on land and offshore. In addition to the PL waves, dispersed waves with group velocities between 0.3 and 0.7 km/sec were observed at ranges less than 10 km. These are identified as Rayleigh waves (LR). Smoothly varying P and S velocity structures for the upper 1 km are obtained by fitting theoretical dispersion curves to the observed PL and LR data.

scholarly journals To the possibility of increasing the efficiency of powerful vibroseismic sources

2019 ◽  
Vol 489 (1) ◽  
pp. 80-83
Author(s):  
A. L. Sobisevich ◽  
R. A. Zhostkov
Keyword(s):  
Parametric Study ◽  
Rayleigh Waves ◽  
Seismic Sources ◽  
Design Features ◽  
Near Surface ◽  
New Approaches ◽  
The Earth ◽  
Numerical Parametric Study

A numerical parametric study of the scattering features of arising from the operation of a vibroseis source Rayleigh waves on near-surface inhomogeneities (seismic barriers) has been performed. In order to find new approaches to the problem of global sensing of the Earth with powerful vibro-seismic sources, the conditions for increasing the efficiency of the emission of volumetric waves due to the design features of seismic barriers were analyzed.

Чувствительность электромагнитно-акустического метода многократной тени с использованием рэлеевских волн при контроле труб нефтяного сортамента

2020 ◽  
pp. 48-57
Author(s):  
О.В. Муравьева ◽  
Л.В. Волкова ◽  
В.В. Муравьев ◽  
М.А. Синцов ◽  
Ю.В. Мышкин ◽  
...  
Keyword(s):  
Rayleigh Waves ◽  
Surface Defects ◽  
Small Diameter ◽  
Acoustic Method ◽  
Shadow Method ◽  
Near Surface ◽  
Research Results ◽  
Informative Parameters ◽  
Natural Surface ◽  
Drill Pipes

The paper proposes algorithms for signals processing obtained by the multiple shadow method using Rayleigh waves propagating in the direction of the envelope pipe, and an electromagnetic-acoustic method of emission-reception. The results of a study of the sensitivity of the method to artificial and natural surface and near-surface defects of workpieces of drill pipes in two frequency ranges are presented. As informative parameters, it is proposed to use the multiple coefficient of detectability, as well as the probabilistic characteristics of dispersion, asymmetry and kurtosis in the analysis of a series of multiple passes, and the criteria for rejection are substantiated. The research results can be used in the development of automated installations and methods for monitoring pipes of small diameter.

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