Love-Wave dispersion and the structure of the Pacific Basin*

1954 ◽  
Vol 44 (1) ◽  
pp. 1-5
Author(s):  
Jack Foord Evernden
Keyword(s):  
Love Wave ◽  
Wave Dispersion ◽  
Love Waves ◽  
Pacific Basin ◽  
Layer Model ◽  
Basin Structure ◽  
Dispersion Data ◽  
The Pacific ◽  
Love Wave Dispersion

abstract By use of the Love-Wave dispersion data for the earthquake of 29 September 1946 (Lat. 5° S, Long. 154° E), a three-layer model of Pacific Basin structure has been derived. The periods of the Love Waves observed varied continuously from 45 seconds to 7 seconds. The model consists of: (a) 2.5 km. with VS equal to 2.31 km/sec.; (b) 11 km. with VS equal to 3.87 km/sec.; (c) bottom with VS equal to 4.52 km/sec. The differences between this model and that found by Raitt using refraction measurements are discussed.

Theoretical Love wave dispersion in a single layer model

1963 ◽  
Vol 55 (1) ◽  
pp. 16-20 ◽  
Author(s):  
Ravindra N. Gupta ◽  
Fraser S. Grant
Keyword(s):  
Love Wave ◽  
Single Layer ◽  
Wave Dispersion ◽  
Layer Model ◽  
Love Wave Dispersion ◽  
Single Layer Model

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.

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.

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