THEORETICAL STUDY ON INTER PERIOD CORRELATION OF RESIDUALS OF GROUND MOTION PREDICTION EQUATION

Abstract

In the conventional probabilistic hazard analysis, the uniform hazard spectrum(UHS) is used as the ground motion which is corresponding to probability of exceedance. The failure probability which is evaluated using UHS is considered to be conservative, because the inter period correlation of residuals of ground motion prediction equation is not incorporated in UHS. Recently, Baker and Cornell(2005) has proposed the concept of conditional mean spectrum(CMS) which takes account of the correlation of the residuals of ground motion prediction equation. In the evaluation of CMS, the correlation of residuals plays key role. Ordinarily the correlation of residuals decreases as the ratio of two periods increases, but it is known that the correlation reversely increases in the short period range although the ratio of two periods increases. It has not been clarified yet why the correlation reversely increases in the short period range. In this paper, the theoretical study on the correlation of residuals of ground motion prediction equation is carried out, and it is shown that reverse increase of correlation of residuals in short period range can be reproduced without assuming any reverse increase of correlation of ground motion itself. The validity of the presented method is also examined by the recent strong motions records obtained by K-NET and KiK-net stations.