Abstract
In the earthquake resistant design and the reliability analysis of structures, the peak ground acceleration (PGA) is widely used as an intensity measure of earthquake motions. Since the PGA is a random variable, its probabilistic characteristics have to be examined. First, we have formulated the probability density function and statistical mean and standard deviation of the PGA ratio, and revealed that utilizing the ratio avoids estimating the mean of the PGA. Next, dense array seismograms in Japan and Taiwan are analyzed to examine the relationship between the statistics of the ratios and the separation distance. Finally, we have shown the standard deviations, means and 50- and 95-percentiles of the ratios, and discussed the expected difference between the PGAs at the neighboring two sites.
