Sensitivity of Response Spectra to ARMA Model Process

The sensitivity analysis in this study focuses on the sensitivity of response spectra to the number of peaks in the envelope function and the order of the Autoregressive Moving Average of order p, q (ARMA( p,q)) process used to represent an earthquake time series. Results consist of two sets of response spectra: one set corresponds to the one peak for envelope function and ARMA(2,1), the second set involves a change in the number of peaks assumed and the order p, q of fitted ARMA(2,1) models. For comparison purposes, response data were normalized by dividing all spectral ordinates by the corresponding ordinates for the one peak, ARMA(2,1) models for the same earthquake. It was conclude that, models of order (2,1) are sufficient to estimate the damage effect of an earthquake with relatively few parameters.