ISSN:
1573-157X
Keywords:
regional amplification
;
path effects
;
coda-length
;
magnituderesidual
;
finite difference
;
SH waves
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geosciences
,
Physics
Notes:
Abstract Seismic ground motion in central Mexico is amplified relative to ground motion observed at the same epicentral distance along the Pacific Coast in a frequency band that includes destructive ground motion at Mexico City. Although several hypothesis have been advanced, at present there is no generally accepted explanation of such amplification. We have analyzed coda-length magnitude data reported by Servicio Sismológico Nacional (SSN) for events recorded during 1993 to increase our understanding of the spatial distribution of this phenomenon. Our results indicate that regional amplification: (a) is detected by magnitude residual computed at each station, relative to the average of SSN network;and (b) is likely related to the crustal structure under the central portion of the Transmexican Volcanic Belt (TMVB). Finally, preliminary wave propagation modelling (using SH wave, finite difference method) suggests that crustal heterogeneity is a possible cause of regional amplification. However, if this is so, it is required that both geometry and velocity distribution vary between the coast and Mexico City.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1009738406881
Permalink
