Publication Date:
2008-04-01
Description:
We simulated strong-motion records from the Umbria-Marche, central Italy, earthquake (M (sub w) 6) of September 1997 using a frequency-dependent S-wave radiation function. We compared the observed acceleration spectra, from strong-motion instruments located in the near field and at regional distances, with those simulated using the stochastic modeling technique of Beresnev and Atkinson (1997, 1998), and modified to account for a frequency-dependent radiation pattern correction. By using the frequency-dependent radiation function previously obtained by Castro et al. (2006), we reduced the overall fitting error of the acceleration spectra by about 9%. In general, we observed that the frequency-dependent radiation pattern correction has a small effect on the spectral amplitudes compared with site effects, which is an important factor controlling the strong-motion records generated by the 1997 Umbria-Marche earthquake. In addition, we modeled the observed ground-motion records using the dynamic corner frequency model of Motazedian and Atkinson (2005) to reproduce the directivity effects, reducing the average error of the spectral amplitudes by 24%. We concluded that although the frequency-dependent radiation pattern correction affects the frequency content of the spectral amplitudes simulated, site and directivity effects are more relevant.
Print ISSN:
0037-1106
Electronic ISSN:
1943-3573
Topics:
Geosciences
,
Physics
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