scholarly journals Crustal structure and surface-wave dispersion, Part III: Theoretical dispersion curves for suboceanic Rayleigh waves*

1953 ◽  
Vol 43 (2) ◽  
pp. 137-144
Author(s):  
W. S. Jardetzky ◽  
Frank Press
Keyword(s):  
Surface Wave ◽  
Crustal Structure ◽  
Rayleigh Waves ◽  
Wave Dispersion ◽  
Dispersion Curves ◽  
Surface Wave Dispersion ◽  
Different Types ◽  
Oceanic Basement ◽  
Rayleigh Wave Dispersion ◽  
Dispersion Part

Abstract Theoretical Rayleigh wave dispersion curves for three different types of sub-oceanic basement layering are presented. Previous conclusions concerning the dispersion of Rayleigh waves across ocean basins are re-examined in the light of the new data.

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 A Feasibility Study on Monitoring Crustal Structure Variations by Direct Comparison of Surface Wave Dispersion Curves from Ambient Seismic Noise

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
K. Muhumuza
Keyword(s):  
Surface Wave ◽  
Rayleigh Wave ◽  
Crustal Structure ◽  
Upper Mantle ◽  
Ambient Noise ◽  
Seismic Velocity ◽  
Wave Dispersion ◽  
Dispersion Curves ◽  
Wave Group ◽  
Surface Wave Dispersion

This work assesses the feasibility of the direct use of surface-wave dispersion curves from seismic ambient noise to gain insight into the crustal structure of Bransfield Strait and detect seasonal seismic velocity changes. We cross-correlated four years of vertical component ambient noise data recorded by a seismic array in West Antarctica. To estimate fundamental mode Rayleigh wave Green’s functions, the correlations are computed in 4-hr segments, stacked over 1-year time windows and moving windows of 3 months. Rayleigh wave group dispersion curves are then measured on two spectral bands—primary (10–30 s) and secondary (5–10 s) microseisms—using frequency-time analysis. We analyze the temporal evolution of seismic velocity by comparing dispersion curves for the successive annual and 3-month correlation stacks. Our main assumption was that the Green’s functions from the cross-correlations, and thus the dispersion curves, remain invariant if the crustal structure remains unchanged. Maximum amplitudes of secondary microseisms were observed during local winter when the Southern Ocean experiences winter storms. The Rayleigh wave group velocity ranges between 2.1 and 3.7 km/s, considering our period range studied. Interannual velocity variations are not much evident. We observe a slight velocity decrease in summer and increase in winter, which could be attributed to the pressure melting of ice and an increase in ice mass, respectively. The velocity anomalies observed within the crust and upper mantle structure correlate with the major crustal and upper mantle features known from previous studies in the area. Our results demonstrate that the direct comparison of surface wave dispersion curves extracted from ambient noise might be a useful tool in monitoring crustal structure variations.

scholarly journals Crustal structure of south-central Mexico estimated from the inversion of surface-wave dispersion curves using genetic and simulated annealing algorithms

2001 ◽  
Vol 40 (3) ◽  
pp. 181-190
Author(s):  
A. Iglesias ◽  
V. M. Cruz-Atienza ◽  
N. M. Shapiro ◽  
S. K. Singh ◽  
J. F. Pacheco
Keyword(s):  
Simulated Annealing ◽  
Surface Wave ◽  
Crustal Structure ◽  
Wave Dispersion ◽  
Dispersion Curves ◽  
Central Mexico ◽  
Surface Wave Dispersion ◽  
South Central ◽  
Annealing Algorithms ◽  
Sobre Todo

A partir de catorce sismos de subducción, agrupados en dos trayectorias (una perpendicular y otra paralela a la línea de costa), se calculó un apilado sobre las curvas de dispersión de velocidad de grupo. Estas curvas promedio fueron invertidas usando, por separado, los métodos de algoritmos genéticos y recristalización simulada. Los resultados muestran fuertes diferencias entre ambos modelos corticales, sobre todo, en los parámetros de la capa más somera y en la localización del Moho. Estas diferencias pueden ser explicadas debido a que la primera trayectoria atraviesa el terreno tectonoestratigráfico "Guerrero" y la segunda el "Oaxaca". La inversión con algoritmos genéticos (GA) probó ser considerablemente más rápida que aquélla con recristalización simulada (SA). Por otro lado SA requiere una pequeña cantidad de memoria y alcanza un desajuste menor que G.A.

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.

Surface-wave dispersion computations

1970 ◽  
Vol 60 (2) ◽  
pp. 321-344 ◽  
Author(s):  
Fred Schwab ◽  
Leon Knopoff
Keyword(s):  
Half Space ◽  
Rayleigh Waves ◽  
Wave Dispersion ◽  
Reduction Technique ◽  
Surface Wave Dispersion ◽  
Single Precision ◽  
Homogeneous Half Space ◽  
Full Control ◽  
Significant Figures ◽  
Rayleigh Wave Dispersion

abstract Fundamental-mode Love- and Rayleigh-wave dispersion computations for multilayered, perfectly-elastic media were studied. The speed of these computations was improved, and the accuracy brought under full control. With sixteen decimal digits employed in these computations, fifteen significant-figure accuracy was found possible with Love waves and twelve to thirteen figure accuracy with Rayleigh waves. In order to ensure that the computed dispersion is correct to a specified accuracy, say σ significant figures, (σ + 1)/4 wavelengths of layered structure must be retained above a homogeneous half-space. To this accuracy, the homogeneous half-space is a sufficient model of the true layering it replaces. Using this result, it was possible to refine the usual layer-reduction technique so as to ensure retention of the specified accuracy while employing reduction. With this reduction technique in effect, and with σ specified below single-precision accuracy, the program can be run entirely in single precision; the specified accuracy is maintained without overflow or loss-of-precision problems being encountered during calculations.

P- and S-wave velocity models from surface wave dispersion curves data transform

2017 ◽  
Author(s):  
Valentina Socco ◽  
Farbod Khosro Anjom ◽  
Cesare Comina ◽  
Daniela Teodor
Keyword(s):  
Surface Wave ◽  
Wave Velocity ◽  
Wave Dispersion ◽  
Dispersion Curves ◽  
S Wave ◽  
Surface Wave Dispersion ◽  
Velocity Models

A model study of elastic waves in a layered sphere

1967 ◽  
Vol 57 (5) ◽  
pp. 959-981
Author(s):  
Victor Gregson
Keyword(s):  
Surface Wave ◽  
Surface Waves ◽  
Elastic Waves ◽  
Wave Dispersion ◽  
Flat Space ◽  
Dispersion Curves ◽  
Body Waves ◽  
Surface Wave Dispersion ◽  
Steel Sphere ◽  
Long Wave

abstract Elastic waves produced by an impact were recorded at the surface of a solid 12.0 inch diameter steel sphere coated with a 0.3 inch copper layer. Conventional modeling techniques employing both compressional and shear piezoelectric transducers were used to record elastic waves for one millisecond at various points around the great circle of the sphere. Body, PL, and surface waves were observed. Density, layer thickness, compressional and shear-wave velocities were measured so that accurate surface-wave dispersion curves could be computed. Surface-wave dispersion was measured as well as computed. Measured PL mode dispersion compared favorably with theoretical computations. In addition, dispersion curves for Rayleigh, Stoneley, and Love modes were computed. Measured surface-wave dispersion showed Rayleigh and Love modes were observed but not Stoneley modes. Measured dispersion compared favorably with theoretical computations. The curvature correction applied to dispersion calculations in a flat space has been estimated to correct dispersion values at long-wave lengths to about one per cent of correct dispersion in a spherical model. Measured dispersion compared with such flat space dispersion corrected for curvature proved accurate within one per cent at long wave lengths. Two sets of surface waves were observed. One set was associated with body waves radiating outward from impact. The other set was associated with body waves reflecting at the pole opposite impact. For each set of surface waves, measured dispersion compared favorably with computed dispersion.

Short-period surface-wave dispersion and shallow crustal structure of central and eastern Tennessee

1992 ◽  
Vol 82 (2) ◽  
pp. 962-979
Author(s):  
Paul C. Yao ◽  
James Dorman
Keyword(s):  
Surface Wave ◽  
Half Space ◽  
Crustal Structure ◽  
Group Velocity Dispersion ◽  
Wave Dispersion ◽  
Surface Wave Dispersion ◽  
Zero Crossing ◽  
Clastic Rocks ◽  
Dispersion Data ◽  
Short Period

Abstract Group velocity dispersion of explosion-generated seismic surface waves with periods ranging from 0.2 to 1.5 sec is used to investigate shallow crustal structure of eastern and central Tennessee. Several modes of both Rayleigh and Love waves can be identified and separated on the seismograms of seven SARSN regional network stations by zero-phase digital filtering. Dispersion data for sinusoidal wave motion were based on digitized zero-crossing times. By forward modeling, we find that a wave guide of at least two layers over a half-space can adequately represent our particular multi-mode, narrow-band observations. In a layered section about 3 km thick, lower velocities characterize outcropping clastic rocks of the Cumberland plateau, and higher velocities correspond to shallow carbonate rocks of the Nashville Dome. Half-space shear velocities of about 3.9 km/sec appear to represent lower Paleozoic carbonate lithology deeper than 2 to 4 km on most of the observed paths. Our best data, interpreted jointly with earlier data of Oliver and Ewing (1958) and of Chen et al. (1989), have a composite period range of 0.2 to 40 sec, but they represent different Appalachian paths. Group velocities over this broad spectrum are satisfied by a complex model with two low-velocity layers. The uniqueness of this model cannot be demonstrated, but it represents important hypotheses concerning regional geologic features that can be tested more rigorously by improved surface-wave dispersion data.

Sign in / Sign up

Export Citation Format

Share Document