Elsevier

Tectonophysics

Volume 218, Issues 1–3, 15 February 1993, Pages 127-140
Tectonophysics

Ground motion in Mexico City during the April 25, 1989, Guerrero earthquake

https://doi.org/10.1016/0040-1951(93)90264-KGet rights and content

Abstract

Instrumental observations of ground motion in Mexico City during the April 25, 1989, Guerrero earthquake were analyzed. Our aim was to understand various aspects of the seismic response of the valley that had not been completely resolved. Such understanding of the basic mechanisms that control the seismic behavior of the valley sediments is crucial in any modeling attempt. The study of vertical motion for this event, which was shown to be practically unaffected by site conditions, lead to the identification of a prominent long-period Rayleigh wave. This, together with the availability of absolute time for some stations, allowed the establishment of a common time reference for all recordings. Horizontal motion, in contrast, was significantly amplified, with large increases in duration, at lake bed sites.

In order to interpret the observed complexity of ground motion we studied two simplified models of soft alluvial valleys. One of these is two-dimensional and it is excited by plane S waves with variable polarization and incidence angles. This model allows three-dimensional response. The other is a three-dimensional axi-symmetric flat valley with a rigid base. Computations were performed in the frequency domain by means of a boundary integral method for the two-dimensional model and using a collocation least-squares technique for the three-dimensional one. Seismograms were obtained through Fourier synthesis. It was found that the irregular soft layer response produces polarization patterns which are similar to the observations, suggesting that the latter are a consequence of three-dimensional effects.

References (27)

  • M. Campillo et al.

    Influence of small lateral variations of a soft surficial layer on seismic ground motion

    Soil Dyn. Earthquake Eng.

    (1990)
  • F.J. Sánchez-Sesma

    Site effects on strong ground motion

    Int. J. Earthquake Eng. Struct Dyn.

    (1987)
  • K. Aki

    Local site effects on strong ground motion, Earthquake Engineering and Soil Dynamics II—Recent advances in ground motion evaluation

  • P.-Y. Bard et al.

    A theoretical investigation of large- and small-scale amplification effects in the Mexico City valley

    Earthquake Spectra

    (1988)
  • M. Campillo et al.

    The incident wavefield in Mexico City during the great Michoácan earthquake and its interaction with the deep basin

    Earthquake Spectra

    (1988)
  • M. Campillo et al.

    Destructive strong ground motion in Mexico City: Source, path and site effects during the great 1985 Michoácan earthquake

    Bull. Seismol. Soc. Am.

    (1989)
  • W.M. Ewing et al.

    Elastic waves in layered media

    (1957)
  • H. Kawase et al.

    A study on the response of a soft basin for incident S, P and Rayleigh waves with special reference to the long duration observed in Mexico City

    Bull. Seismol. Soc. Am.

    (1989)
  • R.J. Marsal et al.

    El subsuelo de la ciudad de México

    (1959)
  • J. Oliver

    A summary of observed seismic surface wave dispersion

    Bull. Seismol. Soc. Am.

    (1962)
  • J. Oliver et al.

    The effect of surficial sedimentary layers on continental surface waves

    Bull. Seismol. Soc. Am.

    (1958)
  • M. Ordaz et al.

    Source spectra and spectral attenuation of seismic waves from Mexican earthquakes, and evidence of amplification in the hill zone of Mexico City

    Bull. Seismol. Soc. Am.

    (1992)
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