The torsional surface wave in a prestressed anisotropic intermediate poroelastic layer of varying heterogeneities

2016 ◽  
Vol 24 (9) ◽  
pp. 1687-1706 ◽  
Author(s):  
Rajneesh Kakar ◽  
Shikha Kakar
Keyword(s):  
Surface Wave ◽  
Wave Speed ◽  
Mass Density ◽  
Wave Dispersion ◽  
Wave Analysis ◽  
Poroelastic Medium ◽  
Surface Wave Dispersion ◽  
Proposed Model ◽  
Saturated Porous Layer ◽  
Torsional Surface Wave

The aim of this paper is to study the behavior of the torsional surface wave in a heterogeneous initially stressed vertical fluid-saturated anisotropic layer sandwiched between inhomogeneous and homogeneous porous half-spaces. It has been considered that the mass density and rigidity of the upper half-space and intermediate layer are space dependent. The proposed model is solved to obtain different dispersion relations for the torsional surface wave in a heterogeneous poroelastic medium lying between two half-spaces. The influence of compressive stress and heterogeneity on torsional surface wave dispersion is shown numerically. It has been observed that heterogeneity, porosity, initial stress of the layer and inhomogeneity of the upper and porosity of lower half-spaces affect the torsional wave speed much. The wave analysis further indicates that the torsional surface waves travel faster in elastic half-spaces in comparison than in the fluid-saturated porous layer.

Dispersion of torsional surface wave in an intermediate vertical prestressed inhomogeneous layer lying between heterogeneous half spaces

2016 ◽  
Vol 23 (19) ◽  
pp. 3292-3305 ◽  
Author(s):  
Rajneesh Kakar ◽  
Shikha Kakar
Keyword(s):  
Surface Wave ◽  
Earthquake Engineering ◽  
Elastic Layer ◽  
Mass Density ◽  
Seismic Wave Propagation ◽  
Inhomogeneous Layer ◽  
Wave Analysis ◽  
Proposed Model ◽  
Torsional Surface Wave ◽  
Torsional Surface Waves

The purpose of this study is to illustrate the propagation of the torsional surface waves in an intermediate inhomogeneous initially stressed vertical elastic layer sandwiched between two heterogeneous half-spaces. It is considered that the mass density and the rigidity of upper and lower half-spaces are space dependent. The proposed model is solved to obtain the different dispersion relations for the torsional surface wave in the elastic medium of different properties. The effects of compressive and tensile stresses along with the heterogeneity on the dispersion of torsional surface wave in the intermediate layer are shown numerically. The wave analysis further indicates that the inhomogeneity, the initial stress of the layer and the heterogeneity of both the half spaces affect the wave velocity remarkably. The results may be useful to understand the nature of seismic wave propagation in geophysical applications and in the field of earthquake engineering.

scholarly journals A fast, convenient program for computation of surface-wave dispersion curves in multilayered media

1961 ◽  
Vol 51 (4) ◽  
pp. 495-502
Author(s):  
Frank Press ◽  
David Harkrider ◽  
C. A. Seafeldt
Keyword(s):  
Surface Wave ◽  
Rayleigh Waves ◽  
High Speed ◽  
Wave Dispersion ◽  
Dispersion Curves ◽  
Mail Order ◽  
Mantle Structure ◽  
Wave Analysis ◽  
Multilayered Media ◽  
Surface Wave Dispersion

Abstract Surface wave analysis has become an important tool for exploration of crustal and mantle structure. The need exists for fast, convenient digital computer programs for computing theoretical dispersion curves and displacements for Rayleigh waves and Love waves. One such program for an IBM 7090 computer is described and made available to the scientific community. Among the conveniences are mail-order service, high speed, and choice of many options.

scholarly journals Accurate Sparse Recovery of Rayleigh Wave Characteristics Using Fast Analysis of Wave Speed (FAWS) Algorithm for Soft Soil Layers

2018 ◽  
Vol 8 (7) ◽  
pp. 1204
Author(s):  
Zhuoshi Chen ◽  
Baofeng Jiang ◽  
Jingjing Song ◽  
Wentao Wang
Keyword(s):  
Surface Wave ◽  
Phase Velocity ◽  
Dispersion Curve ◽  
Wave Speed ◽  
Soft Soil ◽  
Wave Dispersion ◽  
Surface Wave Dispersion ◽  
Fast Analysis ◽  
Soil Layers ◽  
Norm Minimization

This paper presents a novel fast analysis of wave speed (FAWS) algorithm from the waveforms recorded by a random-spaced geophone array based on a compressive sensing (CS) platform. Rayleigh-type seismic surface wave testing is excited by a hammer source and conducted to develop the phase velocity characteristics of the subsoil layers in Shenyang Metro line 9. Data are filtered by a bandpass filter bank to pursue the dispersive profiles of phase velocity at various frequencies. The Rayleigh-type surface-wave dispersion curve for the soil layers at each frequency is conducted by the ℓ1-norm minimization algorithm of CS theory. The traditional frequency-wavenumber transform technique and in-site downhole observation are employed as the comparison of the proposed technique. The experimental results indicate the proposed FAWS algorithm has a good agreement with both the results of conventional even-spaced geophone array and the in-site measurements, which provides an effective and efficient way for accurate non-destructive evaluation of the surface wave dispersion curve of the soil.

Improved Surface Wave Dispersion Models, Amplitude Measurements and Azimuth Estimates

2005 ◽  
Author(s):  
Jeffry L. Stevens ◽  
David A. Adams ◽  
G. E. Baker ◽  
Mariana G. Eneva ◽  
Heming Xu
Keyword(s):  
Surface Wave ◽  
Wave Dispersion ◽  
Dispersion Models ◽  
Surface Wave Dispersion

scholarly journals Imaging the subsurface using induced seismicity and ambient noise: 3-D tomographic Monte Carlo joint inversion of earthquake body wave traveltimes and surface wave dispersion

2020 ◽  
Vol 222 (3) ◽  
pp. 1639-1655
Author(s):  
Xin Zhang ◽  
Corinna Roy ◽  
Andrew Curtis ◽  
Andy Nowacki ◽  
Brian Baptie
Keyword(s):  
Surface Wave ◽  
Ambient Noise ◽  
Velocity Structure ◽  
Joint Inversion ◽  
Body Wave ◽  
Source Parameters ◽  
Wave Dispersion ◽  
Inversion Method ◽  
Surface Wave Dispersion ◽  
Wave Data

SUMMARY Seismic body wave traveltime tomography and surface wave dispersion tomography have been used widely to characterize earthquakes and to study the subsurface structure of the Earth. Since these types of problem are often significantly non-linear and have non-unique solutions, Markov chain Monte Carlo methods have been used to find probabilistic solutions. Body and surface wave data are usually inverted separately to produce independent velocity models. However, body wave tomography is generally sensitive to structure around the subvolume in which earthquakes occur and produces limited resolution in the shallower Earth, whereas surface wave tomography is often sensitive to shallower structure. To better estimate subsurface properties, we therefore jointly invert for the seismic velocity structure and earthquake locations using body and surface wave data simultaneously. We apply the new joint inversion method to a mining site in the United Kingdom at which induced seismicity occurred and was recorded on a small local network of stations, and where ambient noise recordings are available from the same stations. The ambient noise is processed to obtain inter-receiver surface wave dispersion measurements which are inverted jointly with body wave arrival times from local earthquakes. The results show that by using both types of data, the earthquake source parameters and the velocity structure can be better constrained than in independent inversions. To further understand and interpret the results, we conduct synthetic tests to compare the results from body wave inversion and joint inversion. The results show that trade-offs between source parameters and velocities appear to bias results if only body wave data are used, but this issue is largely resolved by using the joint inversion method. Thus the use of ambient seismic noise and our fully non-linear inversion provides a valuable, improved method to image the subsurface velocity and seismicity.

scholarly journals Reliable workflow for inversion of seismic receiver function and surface wave dispersion data: a “13 BB Star” case study

2019 ◽  
Vol 24 (1) ◽  
pp. 101-120
Author(s):  
Kajetan Chrapkiewicz ◽  
Monika Wilde-Piórko ◽  
Marcin Polkowski ◽  
Marek Grad
Keyword(s):  
Surface Wave ◽  
Inverse Problems ◽  
Receiver Function ◽  
Joint Inversion ◽  
Wave Dispersion ◽  
Receiver Functions ◽  
P Wave ◽  
Surface Wave Dispersion ◽  
Phase Velocity Dispersion ◽  
Wide Range

AbstractNon-linear inverse problems arising in seismology are usually addressed either by linearization or by Monte Carlo methods. Neither approach is flawless. The former needs an accurate starting model; the latter is computationally intensive. Both require careful tuning of inversion parameters. An additional challenge is posed by joint inversion of data of different sensitivities and noise levels such as receiver functions and surface wave dispersion curves. We propose a generic workflow that combines advantages of both methods by endowing the linearized approach with an ensemble of homogeneous starting models. It successfully addresses several fundamental issues inherent in a wide range of inverse problems, such as trapping by local minima, exploitation of a priori knowledge, choice of a model depth, proper weighting of data sets characterized by different uncertainties, and credibility of final models. Some of them are tackled with the aid of novel 1D checkerboard tests—an intuitive and feasible addition to the resolution matrix. We applied our workflow to study the south-western margin of the East European Craton. Rayleigh wave phase velocity dispersion and P-wave receiver function data were gathered in the passive seismic experiment “13 BB Star” (2013–2016) in the area of the crust recognized by previous borehole and refraction surveys. Final models of S-wave velocity down to 300 km depth beneath the array are characterized by proximity in the parameter space and very good data fit. The maximum value in the mantle is higher by 0.1–0.2 km/s than reported for other cratons.

Surface Wave Dispersion Imaging Using Improved τ-p Transform Approach

2013 ◽  
Vol 353-356 ◽  
pp. 1196-1202 ◽  
Author(s):  
Jian Qi Lu ◽  
Shan You Li ◽  
Wei Li
Keyword(s):  
Surface Wave ◽  
Phase Shift ◽  
Dispersion Curve ◽  
Wave Dispersion ◽  
S Wave ◽  
Surface Wave Dispersion ◽  
Narrow Frequency Range ◽  
Channel Analysis ◽  
Rayleigh Wave Dispersion

Surface wave dispersion imaging approach is crucial for multi-channel analysis of surface wave (MASW). Because the resolution of inversed S-wave velocity and thickness of a layer are directly subjected to the resolution of imaged dispersion curve. The τ-p transform approach is an efficient and commonly used approach for Rayleigh wave dispersion curve imaging. However, the conventional τ-p transform approach was severely affected by waves amplitude. So, the energy peaks of f-v spectrum were mainly gathered in a narrow frequency range. In order to remedy this shortage, an improved τ-p transform approach was proposed by this paper. Comparison has been made between phase shift and improved τ-p transform approaches using both synthetic and in situ tested data. Result shows that the dispersion image transformed from proposed approach is superior to that either from conventionally τ-p transform or from phase shift approaches.

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