An Analysis of Strong Motion Accelerograms near the Epicenter

Abstract

The strong motion accelerograms of the Matsushiro earthquake were analyzed by various methods. When the velocity and the displacement in the time domain and in the frequency domain are calculated from the accelerogram, various errors may be introduced. Therefore, it is necessary to check and select the methods of data processing according to the purpose of analyses. In this paper, it was shown that the comparison of observed values with theoretical in the form of velocity amplitude spectral density might be most preferable. The main factors affecting the ground vibration during disastrous earthquakes are generally conceived to be: source, path and local geology. The relations between the observed seismogram and the theoretical one were compared when a moving dislocation model was assumed. It was found that the direction of particle motion and the spectral density of observation could be reasonably understood from the theoretical point of view.