An error analysis of frequency-time analysis

1983 ◽  
Vol 73 (1) ◽  
pp. 143-155
Author(s):  
Chi-Chin Feng ◽  
Ta-liang Teng
Keyword(s):  
Surface Wave ◽  
Matched Filter ◽  
Data Extraction ◽  
Wave Dispersion ◽  
Dispersion Analysis ◽  
Time Analysis ◽  
Surface Wave Dispersion ◽  
Period Range ◽  
Dispersion Measurement ◽  
Short Period

abstract The temporal resolution and accuracy of frequency-time analysis (FTAN) as applied to surface-wave dispersion analysis are examined for a period range from 10 to 200 sec. The constant relative bandwidth filter (Dziewonski et al., 1969), optimum bandwidth filter (Inston et al., 1971), and display-equalized filter (Nyman and Landisman, 1977) are carefully examined with respect to their adequacy of application over a broad period range. Among these Gaussian filters, the optimum bandwidth filter gives a better performance for relatively short-period (less than 50 sec) dispersion measurement. To measure surface-wave dispersion for a broad period range, a “matched-filter FTAN” technique is introduced by modifying the “residual dispersion measurement” technique (Dziewonski et al., 1972). A detailed numerical analysis is made on this new technique; the result demonstrates a significant improvement on both the resolution and the accuracy of surface-wave dispersion data extraction over a broad period range up to at least 200 sec.

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.

Seismic studies in central and eastern Tennessee

1978 ◽  
Vol 68 (4) ◽  
pp. 1081-1094
Author(s):  
E. S. Sodbinow ◽  
G. A. Bollinger
Keyword(s):  
Surface Wave ◽  
Theoretical Models ◽  
Wave Dispersion ◽  
Time Frame ◽  
Low Noise ◽  
Cumberland Plateau ◽  
Surface Wave Dispersion ◽  
Mode Dispersion ◽  
Short Period ◽  
Wave Trains

abstract Some of the seismic characteristics of Tennessee were investigated by means of a short-period surface-wave dispersion study in central Tennessee and a microearthquake survey of the eastern portion of the state. The tripartite method of phase velocity determination was applied to data from a 4-element SPZ array at the Cumberland Plateau Observatory (CPO). Seven short-period (0.5 to 1.4 sec.) surface-wave trains were analyzed. These wave trains exhibited both fundamental and first higher mode dispersion. Theoretical models, consisting of 2 or 3 layers over a half-space were developed that explain the observed dispersion. The layers, which model the surficial sediments of the region, range in total thickness from 1.6 to 2.1 km and have shear velocities from 1.70 to 3.10 km/sec. A 5-station array of portable seismographs was deployed in eastern Tennessee and 2 months of operation yielded 3000 low-noise hours of data. Eleven microearthquakes −1.3 ≦ M ≦ 1.1 were recorded during that time frame indicating that, at least for periods of several weeks, the microseismicity of eastern Tennessee can be very low.

Crustal structure of northern and southern Tibet from surface wave dispersion analysis

2003 ◽  
Vol 108 (B2) ◽  
Author(s):  
Richard Rapine ◽  
Frederik Tilmann ◽  
Michael West ◽  
James Ni ◽  
Arthur Rodgers
Keyword(s):  
Surface Wave ◽  
Crustal Structure ◽  
Wave Dispersion ◽  
Dispersion Analysis ◽  
Surface Wave Dispersion ◽  
Southern Tibet

Age-related changes in the viscoelasticity of rabbit lens characterised by surface wave dispersion analysis

2022 ◽  
Vol 52 (1) ◽  
pp. 42-47
Author(s):  
H Zhang ◽  
M Singh ◽  
F Zvietcovich ◽  
K V Larin ◽  
S R Aglyamov
Keyword(s):  
Surface Wave ◽  
Young’S Modulus ◽  
Shear Viscosity ◽  
Young's Modulus ◽  
Viscosity Coefficient ◽  
Wave Dispersion ◽  
Dispersion Analysis ◽  
Optical Coherence ◽  
Surface Wave Dispersion

Abstract The viscoelastic properties of the young and mature rabbit lenses in situ are evaluated using wave-based optical coherence elastography (OCE). Surface waves in the crystalline lens are generated using acoustic radiation force (ARF) focused inside the eyeball. Surface-wave dispersion is measured with a phase-stabilised optical coherence tomography (OCT) system. The Young's modulus and shear viscosity coefficient are quantified based on a Scholte wave model. The results show that both elasticity and viscosity are significantly different between the young and mature lenses. The Young's modulus of the lenses increased with age from 7.74 ± 1.56 kPa (young) to 15.15 ± 4.52 kPa (mature), and the shear viscosity coefficient increased from 0.55 ± 0.04 Pa s (young) and 0.86 ± 0.13 Pa s (mature). It is shown that the combination of ARF excitation, OCE imaging, and dispersion analysis enables nondestructive quantification of lenticular viscoelasticity in situ and shows promise for in vivo applications.

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