scholarly journals Field investigation of Love waves in near-surface seismology

Geophysics ◽  
2008 ◽  
Vol 73 (3) ◽  
pp. G1-G6 ◽  
Author(s):  
Robert Eslick ◽  
Georgios Tsoflias ◽  
Don Steeples
Keyword(s):  
Surface Layer ◽  
Data Acquisition ◽  
Love Wave ◽  
Field Data ◽  
Field Investigation ◽  
Love Waves ◽  
Frequency Range ◽  
Minimum Thickness ◽  
Near Surface ◽  
Wave Data

We examine subsurface conditions and survey parameters suitable for successful exploitation of Love waves in near-surface investigations. Love-wave generation requires the existence of a low shear-velocity surface layer. We examined the minimum thickness of the near-surface layer necessary to generate and record usable Love-wave data sets in the frequency range of [Formula: see text]. We acquired field data on a hillside with flat-lying limestone and shale layers that allowed for the direct testing of varying overburden thicknesses as well as varying acquisition geometry. The resulting seismic records and dispersion images were analyzed, and the Love-wave dispersion relation for two layers was examined analytically. We concluded through theoretical and field data analysis that a minimum thickness of [Formula: see text] of low-velocity material is needed to record usable data in the frequency range of interest in near-surface Love-wave surveys. The results of this study indicate that existing guidelines for Rayleigh-wave data acquisition, such as receiver interval and line length, are also applicable to Love-wave data acquisition.

Multichannel analysis of Love waves in a 3D seismic acquisition system

Geophysics ◽  
2016 ◽  
Vol 81 (5) ◽  
pp. EN67-EN74 ◽  
Author(s):  
Yudi Pan ◽  
Jianghai Xia ◽  
Yixian Xu ◽  
Lingli Gao
Keyword(s):  
Love Wave ◽  
Wave Dispersion ◽  
Love Waves ◽  
3D Seismic ◽  
Near Surface ◽  
Wave Data ◽  
Multichannel Analysis ◽  
Seismic Acquisition ◽  
Love Wave Dispersion ◽  
Receiver Point

Multichannel analysis of Love waves (MALW) analyzes high-frequency Love waves to determine near-surface S-wave velocities, and it is getting increasing attention in the near-surface geophysics and geotechnique community. Based on 2D geometry spread, in which sources and receivers are placed along the same line, current MALW fails to work in a 3D seismic acquisition system. This is because Love-wave particle motion direction is perpendicular to its propagation direction, which makes it difficult to record a Love-wave signal in 3D geometries. We have developed a method to perform MALW with data acquired in 3D geometry. We recorded two orthogonal horizontal components (inline and crossline components) at each receiver point at the same time. By transforming the raw data from rectangular coordinates (inline and crossline components) to radial-transverse coordinates (radial and transverse components), we recovered Love-wave data along the transverse direction at each receiver point. To achieve a Love-wave dispersion curve, the recovered Love-wave data were first transformed into a conventional receiver offset domain, and then transformed into the frequency-velocity ([Formula: see text]-[Formula: see text]) domain. Love-wave dispersion curves were picked along the continuous dispersive energy peaks in the [Formula: see text]-[Formula: see text] domain. The validity of our proposed method was verified by two synthetic tests and a real-world example.

Full waveform inversion of SH- and Love-wave data in near-surface prospecting

2017 ◽  
Vol 65 ◽  
pp. 216-236 ◽  
Author(s):  
E. Dokter ◽  
D. Köhn ◽  
D. Wilken ◽  
D. De Nil ◽  
W. Rabbel
Keyword(s):  
Love Wave ◽  
Waveform Inversion ◽  
Full Waveform Inversion ◽  
Near Surface ◽  
Wave Data ◽  
Full Waveform

scholarly journals Field investigation of Love waves in near‐surface seismology

2007 ◽  
Author(s):  
Robert Eslick ◽  
Georgios Tsoflias ◽  
Don Steeples
Keyword(s):  
Field Investigation ◽  
Love Waves ◽  
Near Surface

Wave-equation dispersion inversion of Love waves

Geophysics ◽  
2019 ◽  
Vol 84 (5) ◽  
pp. R693-R705 ◽  
Author(s):  
Jing Li ◽  
Sherif Hanafy ◽  
Zhaolun Liu ◽  
Gerard T. Schuster
Keyword(s):  
Wave Equation ◽  
Wave Velocity ◽  
Rayleigh Waves ◽  
Love Wave ◽  
Field Data ◽  
Wave Dispersion ◽  
Dispersion Curves ◽  
Love Waves ◽  
S Wave ◽  
Love Wave Dispersion

We present a theory for wave-equation inversion of Love-wave dispersion curves, in which the misfit function is the sum of the squared differences between the wavenumbers along the predicted and observed dispersion curves. Similar to inversion of Rayleigh-wave dispersion curves, the complicated Love-wave arrivals in traces are skeletonized as simpler data, namely, the picked dispersion curves in the [Formula: see text] domain. Numerical solutions to the SH-wave equation and an iterative optimization method are then used to invert these dispersion curves for the S-wave velocity model. This procedure, denoted as wave-equation dispersion inversion of Love waves (LWD), does not require the assumption of a layered model or smooth velocity variations, and it is less prone to the cycle-skipping problems of full-waveform inversion. We demonstrate with synthetic and field data examples that LWD can accurately reconstruct the S-wave velocity distribution in a laterally heterogeneous medium. Compared with Rayleigh waves, inversion of the Love-wave dispersion curves empirically exhibits better convergence properties because they are completely insensitive to the P-velocity variations. In addition, Love-wave dispersion curves for our examples are simpler than those for Rayleigh waves, and they are easier to pick in our field data with a low signal-to-noise ratio.

Perturbational and nonperturbational inversion of Love-wave velocities

Geophysics ◽  
2019 ◽  
Vol 85 (1) ◽  
pp. F19-F26 ◽  
Author(s):  
Matthew M. Haney ◽  
Victor C. Tsai
Keyword(s):  
Wave Velocity ◽  
Love Wave ◽  
Cutoff Frequency ◽  
Forward Modeling ◽  
Love Waves ◽  
Initial Model ◽  
S Wave ◽  
Near Surface ◽  
The Matrix ◽  
Group Velocities

We describe a set of MATLAB codes to forward model and invert Love-wave phase or group velocities. The forward modeling is based on a finite-element method in the frequency-wavenumber domain, and we obtain the different modes with an eigenvector-eigenvalue solver. We examine the issue of parasitic modes that arises for modeling Love waves, in contrast to the Rayleigh wave case, and how to discern parasitic from physical modes. Once the matrix eigenvector-eigenvalue problem has been solved for Love waves, we show a straightforward technique to obtain sensitivity kernels for S-wave velocity and density. In practice, the sensitivity of Love waves to density is relatively small and inversions only aim to estimate the S-wave velocity. Two types of inversion accompany the forward-modeling codes: One is a perturbational scheme for updating an initial model, and the other is a nonperturbational method that is well-suited for defining a good initial model. The codes are able to implement an optimal nonuniform layering designed for Love waves, invert combinations of phase and group velocity measurements of any mode, and seamlessly handle the transition from guided to leaky modes below the cutoff frequency. Two software examples demonstrate use of the codes at near-surface and crustal scales.

scholarly journals Influence of Poroelasticity of the Surface Layer on the Surface Love Wave Propagation

2018 ◽  
Vol 85 (5) ◽  
Author(s):  
Adil El Baroudi
Keyword(s):  
Wave Propagation ◽  
Surface Layer ◽  
Phase Velocity ◽  
Dispersion Equation ◽  
Love Wave ◽  
Wave Attenuation ◽  
Love Waves ◽  
Velocity Variation ◽  
Fluid Viscosity ◽  
Benchmark Solutions

This work presents a theoretical method for surface love waves in poroelastic media loaded with a viscous fluid. A complex analytic form of the dispersion equation of surface love waves has been developed using an original resolution based on pressure–displacement formulation. The obtained complex dispersion equation was separated in real and imaginary parts. mathematica software was used to solve the resulting nonlinear system of equations. The effects of surface layer porosity and fluid viscosity on the phase velocity and the wave attenuation dispersion curves are inspected. The numerical solutions show that the wave attenuation and phase velocity variation strongly depend on the fluid viscosity, surface layer porosity, and wave frequency. To validate the original theoretical resolution, the results in literature in the case of an homogeneous isotropic surface layer are used. The results of various investigations on love wave propagation can serve as benchmark solutions in design of fluid viscosity sensors, in nondestructive testing (NDT) and geophysics.

Recombination Characteristics of Single-Crystalline Silicon Wafers with a Damaged Near-Surface Layer

2013 ◽  
Vol 58 (2) ◽  
pp. 142-150 ◽  
Author(s):  
A.V. Sachenko ◽  
◽  
V.P. Kostylev ◽  
V.G. Litovchenko ◽  
V.G. Popov ◽  
...  
Keyword(s):  
Surface Layer ◽  
Crystalline Silicon ◽  
Silicon Wafers ◽  
Single Crystalline Silicon ◽  
Near Surface ◽  
Single Crystalline

Field Investigation of a New Recharge Approach for ASR Projects in Near-Surface Aquifers

Ground Water ◽  
2015 ◽  
Vol 54 (3) ◽  
pp. 425-433 ◽  
Author(s):  
Gaisheng Liu ◽  
Steven Knobbe ◽  
Edward C. Reboulet ◽  
Donald O. Whittemore ◽  
Falk Händel ◽  
...  
Keyword(s):  
Field Investigation ◽  
Near Surface
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