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Preliminary empirical model for scaling fourier amplitude spectra of strong ground acceleration in terms of modified mercalli intensity and recording site conditions
Author(s) -
Trifunac M. D.
Publication year - 1979
Publication title -
earthquake engineering and structural dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.218
H-Index - 127
eISSN - 1096-9845
pISSN - 0098-8847
DOI - 10.1002/eqe.4290070106
Subject(s) - mercalli intensity scale , amplitude , scaling , acceleration , intensity (physics) , fourier transform , spectral line , geology , magnitude (astronomy) , seismology , fourier analysis , coherence (philosophical gambling strategy) , peak ground acceleration , spectral acceleration , physics , computational physics , optics , ground motion , mathematics , geometry , classical mechanics , quantum mechanics , astronomy
This paper presents an empirical model for scaling Fourier amplitude spectra of ground acceleration during strong earthquake shaking in terms of the reported Modified Mercalli Intensity (MMI) and the simplified characteristics of the geologic environment at the recording station. This analysis shows that (i) for the intermediate and high‐frequency motions the spectral amplitudes approximately double for every level of the MMI; that (ii) the uncertainties associated with estimation of Fourier spectral amplitudes in terms of MMI are not greater than the uncertainties associated with similar estimation in terms of earthquake magnitude and epicentral distance; that (iii) the high frequency spectral amplitudes tend to be greater on basement rock sites relative to alluvium sites, with this trend being reversed for the low‐frequency spectral amplitudes; and that (iv) the spectral amplitudes of very high‐frequency vertical shaking are equal to or higher than the corresponding spectral amplitudes for horizontal shaking.