Generation of artificial earthquake accelerograms compatible with mean and mean ± standard deviation

The sustained dissemination of database of recorded accelerograms along with the increasing number of strong-motion networks installed worldwide revealed that the current methodologies for simulating artificial earthquakes possess the drawback that the simulated time-histories do not manifest the variability observed for natural accelerograms. As a consequence, the dispersion of resulting structural response analysis can be underestimated. In order to take into account the natural variability of earthquakes, a methodology for simulating artificial earthquake accelerograms matching mean and mean ± standard deviation response spectra is proposed in this paper. This dispersion can be determined from attenuation relationships or evaluated from selected accelerograms of a strong-motion database. The procedure requires the definition of an evolutionary response-spectrum-compatible power spectral density function with random parameters. The simulated ground motion time-histories will manifest variability so that one observed in natural records