PREDICTION OF WAVEFORMS OF LONG-PERIOD GROUND MOTIONS FOR HYPOTHETICAL EARTHQUAKES USING EMPIRICAL REGRESSION RELATIONS OF RESPONSE SPECTRA AND PHASE SPECTRA

Abstract

We develop empirical regression relations for estimating waveforms of horizontal and vertical ground motions in a period range of 0.1 to 10 seconds caused by subduction-zone and crustal earthquakes using many strong motion records all in Japan. The relations are provided for 5 % and 1 % damped acceleration response spectra, energy spectrum, average of group delay time, and standard deviation of group delay time. The waveforms with site-specific amplification and phase spectra are easily calculated by the empirical relations using the outer-fault parameters, rupture starting points, delay time among rupture starting points, and the location of the strong motion stations in interest. We show that waveforms calculated by the empirical relations for the hypothetical Nankai earthquake are consistent with waveforms calculated by the theoretical method using three dimensional structure model and inner-fault parameters as well as outer-fault parameters in previous studies.