Summary
The dispersion of higher modes of surface waves over a region covered by an array of stations can be measured by applying a frequency-wavenumber transform to segments of the signals in these stations, centered at a number of group-velocities. Thus, at a fixed period, modes appear as separate maxima in a display of the power spectrum on a phase-velocity vs. group velocity plane.
For regions of mild lateral heterogeneity, the main source of error is shown to be due to the inadequacy of the array-response. Numerical experiments with synthetic signals indicate that a precision of the order of 1% can be obtained with a realistic number of stations. Improvements should be obtained by averaging data obtained from different events. The danger of misidentification of modes can be reduced by iteratively removing the sidelobes from the mode-separation diagram.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
H. Bungum andJ. Capon (1974),Coda Pattern and Multipath Propagation of Rayleigh Waves at Norsar, Phys. Earth Plan. Int.9, 111–127.
J. Capon (1970),Applications of Detection and Estimation Theory to Large Array Seismology, Proc. IEEE58, 760–770.
M. Cara (1976),Observations d'Onde Sa de type SH, Pure appl. Geophys.,114, 141–157.
S. Crampin (1967),Coupled Rayleigh-Love Second Modes, Geophys. J. R. astr. Soc.12, 229–235.
J. W. Cooley andJ. W. Tukey (1965),An Algorithm for the Machine Computation of Complex Fourier Series, Math. Comp.19, 297–301.
A. M. Dziewonski andA. L. Hales (1972),Numerical Analysis of Dispersed Seismic Waves, Meth. Comp. Phys.11, 39–85.
D. W. Forsyth (1975),A New Method for the Analysis of Multi-Mode Surface Wave Dispersion: Application to Love Wave Propagation in the East Pacific, Bull. Seism. Soc. Am.65, 323–342.
F. Gilbert andA. M. Dziewonski (1975),An Application of Normal Mode Theory to the Retrieval of Structural Parameters and Source Mechanisms from Seismic Spectra, Phil. Trans. Roy. Soc.278, 187–269.
B. Gold andC. M. Rader,Digital Processing of Signals (McGraw-Hill, New York, 1969).
J. A. Högbom (1974),Aperture Synthesis with a Non-Regular Distribution of Interferometer Baselines, Astron. Astrophys. Suppl.15, 417–426.
M. Landisman, A. M. Dziewonski andY. Sato (1969),Recent improvements in the Analysis of Surface Wave Observations, Geophys. J. R. astr. Soc.17, 369–413.
H. Mack andE. Smart (1973),Automatic Processing of Multi-Array Long Period Seismic Data, Geophys. J. R. astr. Soc.35, 215–224.
R. I. Madariaga (1972),Toroidal Free Oscillations of the Laterally Heterogeneous Earth, Geophys. J.R. astr. Soc.27, 81–100.
J. A. Mendiguren (1973),Identification of Free Oscillation Spectral Peaks for 1970 July 31, Columbian Deep Shock using the Excitation Criterion, Geophys. J.R. astr. Soc.33, 281.
G. Nolet (1975),Higher Rayleigh Modes in Western Europe, Geophys. Res. Lett.,2, 60–62.
G. F. Panza, F. A. Schwab andL. Knopoff (1973),Multimode Surface Waves for Selected Focal Mechanisms, I, Dip-Slip Sources on a Vertical Fault Plane, Geophys. J.R. astr. Soc.34, 265–278.
G. F. Panza, F. A. Schwab andL. Knopoff (1975a),Multimode Surface Waves for Selected Focal Mechanisms, II, Dip-Slip Sources, Geophys. J.R. astr. Soc.42, 931–944.
G. F. Panza, F. A. Schwab andL. Knopoff (1975b),Multimode Surface Waves for Selected Focal Mechanisms III, Strike-Slip Sources, Geophys. J.R. astr. Soc.42, 945–956.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Nolet, G., Panza, G.F. Array analysis of seismic surface waves: Limits and possibilities. PAGEOPH 114, 775–790 (1976). https://doi.org/10.1007/BF00875787
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00875787