Rayleigh- and Love-wave dispersion up to 140-second-period range in the Indonesia-Philippine region

1975 ◽  
Vol 65 (2) ◽  
pp. 507-521
Author(s):  
Harsh K. Gupta ◽  
Kazuo Hamada
Keyword(s):  
Rayleigh Wave ◽  
Group Velocity ◽  
Love Wave ◽  
Active Regions ◽  
Wave Dispersion ◽  
Wave Group ◽  
Period Range ◽  
Moving Window Analysis ◽  
Love Wave Dispersion ◽  
Group Velocities

abstract Group velocities for Rayleigh waves extending to 140-sec-period range have been determined for 10 paths in the Indonesia-Philippine region using moving window analysis. The group velocities for five of these paths have been determined from the vertical as well as the longitudinal components and the values obtained from the two components tally with each other. It has also been possible to obtain Love-wave group velocities for three of these paths. On the basis of group-velocity values and regions covered, the observed Rayleigh-wave group-velocity data could be divided into three groups. The first group includes data for paths mostly confined to deep ocean and the observed data could be explained by standard oceanic models such as 8099. The second group includes data for paths lying partially within seismically active regions and models ARC-1 and ALRDG-9 fit with these data. The third group shows still lower group velocities for paths entirely confined to seismically active regions. The shear velocities inferred from Love-wave dispersion data are higher than those inferred from Rayleigh-wave data. In general, the group velocities varied greatly within small distances even in the longer period range, indicating strong lateral heterogeneities in the mantle.

Rayleigh wave group velocities in central California

1968 ◽  
Vol 58 (3) ◽  
pp. 881-890
Author(s):  
D. J. Sutton
Keyword(s):  
Rayleigh Wave ◽  
Group Velocity ◽  
Sierra Nevada ◽  
Wave Dispersion ◽  
Wave Group ◽  
Period Range ◽  
Central California ◽  
Great Valley ◽  
Rayleigh Wave Dispersion ◽  
Group Velocities

abstract Experimentally determined Rayleigh-wave dispersion curves of group velocity are given for five paths from NTS to stations in the network operated by the Seismographic Station at U.C. Berkeley. Periods observed range from 4 to 14 seconds. Although, as expected, two different paths from NTS to the western edge of the Sierra Nevada resulted in similar curves, efforts to find empirical curves appropriate to the Great Valley and the Coast Ranges on the assumption of provinces with parallel boundaries were not successful. Estimates of group velocity across the Great Valley along the path NTS to BRK indicate velocities, in the period range 5–9 seconds, considerably lower than would be expected from crustal models so far suggested.

Worldwide investigation of the mantle Rayleigh-wave group velocities

1973 ◽  
Vol 63 (1) ◽  
pp. 271-281
Author(s):  
Harsh K. Gupta ◽  
Tetsuo Santô
Keyword(s):  
Rayleigh Wave ◽  
Velocity Dispersion ◽  
Group Velocity Dispersion ◽  
Great Circle ◽  
Wave Group ◽  
High Group ◽  
Period Range ◽  
Very High ◽  
Group Velocities ◽  
Existing Data

abstract An attempt to apply the crossing path technique to the division of the globe into similar regions of mantle Rayleigh-wave group-velocity dispersion characteristics failed because of the paucity of existing data (for about 80 great-circle paths). As a first step to achieve this goal, mantle Rayleigh-wave group velocities have been obtained for 31 new great-circle paths in the 80- to 240-sec period range. The data have been divided into four groups on the basis of dispersion behavior and compared with Dziewonski's (1971) results. An interesting finding has been the very high group velocities for the 6-MUN path, higher than any reported so far.

scholarly journals A MATLAB Package for Calculating Partial Derivatives of Surface-Wave Dispersion Curves by a Reduced Delta Matrix Method

2019 ◽  
Vol 9 (23) ◽  
pp. 5214 ◽  
Author(s):  
Wu ◽  
Wang ◽  
Su ◽  
Zhang
Keyword(s):  
Surface Wave ◽  
Group Velocity ◽  
Love Wave ◽  
Wave Dispersion ◽  
Dispersion Curves ◽  
Wave Group ◽  
Surface Wave Dispersion ◽  
Partial Derivatives ◽  
Matlab Package ◽  
Derivatives Of

Various surface-wave exploration methods have become increasingly important tools in investigating the properties of subsurface structures. Inversion of the experimental dispersion curves is generally an indispensable component of these methods. Accurate and reliable calculation of partial derivatives of surface-wave dispersion curves with respect to parameters of subsurface layers is critical to the success of these approaches if the linearized inversion strategies are adopted. Here we present an open-source MATLAB package, named SWPD (Surface Wave Partial Derivative), for modeling surface-wave (both Rayleigh- and Love-wave) dispersion curves (both phase and group velocity) and particularly for computing their partial derivatives with high precision. The package is able to compute partial derivatives of phase velocity and of Love-wave group velocity analytically based on the combined use of the reduced delta matrix theory and the implicit function theorem. For partial derivatives of Rayleigh-wave group velocity, a hemi-analytical method is presented, which analytically calculates all the first-order partial differentiations and approximates the mixed second-order partial differentiation term with a central difference scheme. We provide examples to demonstrate the effectiveness of this package, and demo scripts are also provided for users to reproduce all results of this paper and thus to become familiar with the package as quickly as possible.

scholarly journals Computation of surface wave dispersion for multilayered anisotropic media

1962 ◽  
Vol 52 (2) ◽  
pp. 321-332 ◽  
Author(s):  
David G. Harkrider ◽  
Don L. Anderson
Keyword(s):  
Surface Wave ◽  
Rayleigh Wave ◽  
Rayleigh Waves ◽  
Love Wave ◽  
Transversely Isotropic ◽  
Wave Dispersion ◽  
Surface Wave Dispersion ◽  
Independent Evidence ◽  
Anisotropic Layers ◽  
Love Wave Dispersion

ABSTRACT With the program described in this paper it is now possible to compute surface wave dispersion in a solid heterogeneous halfspace containing up to 200 anisotropic layers. Certain discrepancies in surface wave observations, such as disagreement between Love and Rayleigh wave data and other independent evidence, suggest that anisotropy may be important in some seismological problems. In order to study the effect of anisotropy on surface wave dispersion a program was written for an IBM 7090 computer which will compute dispersion curves and displacements for Rayleigh waves in a layered halfspace in which each layer is transversely isotropic. A simple redefinition of parameters makes it possible to use existing programs to compute Love wave dispersion.

scholarly journals Horizontally orthogonal distributed acoustic sensing array for earthquake- and ambient-noise-based multichannel analysis of surface waves

2020 ◽  
Vol 222 (3) ◽  
pp. 2147-2161
Author(s):  
Bin Luo ◽  
Whitney Trainor-Guitton ◽  
Ebru Bozdağ ◽  
Lisa LaFlame ◽  
Steve Cole ◽  
...  
Keyword(s):  
Rayleigh Wave ◽  
Surface Waves ◽  
Love Wave ◽  
Ambient Noise ◽  
Wave Dispersion ◽  
Wave Component ◽  
Multichannel Analysis ◽  
Distributed Acoustic Sensing ◽  
Love Wave Dispersion

SUMMARY A 2-D orthogonal distributed acoustic sensing (DAS) array designed for seismic experiments was buried horizontally beneath the Kafadar Commons Geophysical Laboratory on the Colorado School of Mines campus at Golden, Colorado. The DAS system using straight fibre-optic cables is a cost-efficient technology that enables dense seismic array deployment for long-term seismic monitoring, favouring both earthquake-based and ambient-noise-based surface wave analysis for subsurface characterization. In our study, the horizontally orthogonal DAS array records ambient noise data for a period of about two months from November 2018 to January 2019. During this time, the array also detected seismic signals from an ML3.6 earthquake at Glenwood Springs, Colorado, which exhibit opposite signal polarities in the orthogonal DAS section recordings. We derive the transformation matrix for DAS strain measurements in horizontally orthogonal cables to retrieve both Rayleigh and Love wave dispersion information from the single-component DAS signals using the 2-D multichannel analysis of surface waves method. In addition, ambient noise interferometry is applied to long-term DAS noise recordings. Our theoretical derivation demonstrates that Rayleigh and Love wave Green's functions are coupled in the noise cross-correlation functions (NCFs) of DAS receiver pairs. Stacking NCFs over the horizontally orthogonal DAS array can constructively recover the radial Rayleigh wave component but destructively suppress the Love wave component. The multimodal Monte Carlo inversion of the earthquake-based Rayleigh wave and Love wave dispersion measurements and the noise-based Rayleigh wave measurement reveals a 1-D layered structure that agrees qualitatively with geological surveys of the site. Our study demonstrates that although straight fibre-optic cables lack broadside sensitivity, using appropriate DAS array configuration and seismic array methods can extend the seismic acquisition ability of DAS and enable its application to a broad range of scenarios.

Crustal structure of the Tibetan Plateau: A surface-wave study by a moving window analysis

1977 ◽  
Vol 67 (3) ◽  
pp. 735-750
Author(s):  
Kin-Yip Chun ◽  
Toshikatsu Yoshii
Keyword(s):  
Tibetan Plateau ◽  
Crustal Structure ◽  
The Tibetan Plateau ◽  
Moving Window ◽  
Low Velocity ◽  
Period Range ◽  
Window Analysis ◽  
Dispersion Data ◽  
Moving Window Analysis ◽  
Group Velocities

abstract Group velocities of fundamental-mode Rayleigh and Love waves are analyzed to construct a crustal structure of the Tibetan Plateau. A moving window analysis is employed to compute group velocities in a wide period range of 7 to 100 sec for 17 individual paths. The crustal models derived from these dispersion data indicate that under the Tibetan Plateau the total crustal thickness is about 70 km and that the crustal velocities are generally low. The low velocities are most probably caused by high temperatures. A low-velocity zone located at an intermediate depth within the crust appears to be strongly demanded by the observed dispersion data. The main features of the proposed crustal structure will place stringent constraints on future tectonic models of the Tibetan Plateau which is generally regarded as a region of active deformation due to the continent-continent collision between India and Asia.

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.

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