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| Titel |
On the behavior of site effects in central Mexico (the Mexican volcanic belt – MVB), based on records of shallow earthquakes that occurred in the zone between 1998 and 2011 |
| VerfasserIn |
A. Clemente-Chavez, F. R. Zúñiga, J. Lermo, A. Figueroa-Soto, C. Valdés, M. Montiel, O. Chavez, M. Arroyo |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Sciences ; 14, no. 6 ; Nr. 14, no. 6 (2014-06-04), S.1391-1406 |
| Datensatznummer |
250118489
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| Publikation (Nr.) |
 copernicus.org/nhess-14-1391-2014.pdf |
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| Zusammenfassung |
The Mexican volcanic belt (MVB) is a seismogenic zone that transects the
central part of Mexico with an east–west orientation. The seismic risk and
hazard of this seismogenic zone has not been studied in detail due to the
scarcity of instrumental data as well as because seismicity in the
continental regime of central Mexico is not too frequent. However, it is
known that there are precedents of large earthquakes (Mw > 6.0)
that have taken place in this zone. The valley of Mexico City (VM) is the
sole zone, within the MVB, that has been studied in detail. Studies have
mainly focused on the ground amplification during large events such as the
1985 subduction earthquake that occurred off coast of Michoacán. The
purpose of this article is to analyze the behavior of site effects in the MVB
zone based on records of shallow earthquakes (data not reported before) that
occurred in the zone between 1998 and 2011. We present a general overview of
site effects in the MVB, a classification of the stations in order to reduce
the uncertainty in the data when obtaining attenuation parameters in future
works, as well as some comparisons between the information presented here and
that presented in previous studies.
A regional evaluation of site effects and Fourier acceleration spectrum
(FAS) shape was estimated based on 80 records of 22 shallow earthquakes
within the MVB zone. Data of 25 stations were analyzed. Site effects were
estimated by using the horizontal-to-vertical spectral ratio (HVSR)
methodology. The results show that seismic waves are less amplified in the
northeast sites of the MVB with respect to the rest of the zone and that it
is possible to classify two groups of stations: (1) stations with negligible
site amplification (NSA) and (2) stations with significant site amplification
(SSA). Most of the sites in the first group showed small (<3)
amplifications while the second group showed amplifications ranging from 4
to 6.5 at frequencies of about 0.35, 0.75, 15 and 23 Hz. With these groups
of stations, average levels of amplification were contrasted for the first
time with those caused by the subduction zone earthquakes. With respect to
the FAS shapes, most of them showed similarities at similar epicentral
distances. Finally, some variations of site effects were found when compared
to those obtained in previous studies on different seismicity regions. These
variations were attributed to the location of the source.
These aspects help to advance the understanding about the amplification
behavior and of the expected seismic risk on central Mexico due to large
earthquakes within the MVB seismogenic zone. |
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