PREDICTION APPROACH OF RISE PART OF REAL-TIME SEISMIC INTENSITY

Abstract

In this study, we proposed a method to simply predict the rise part of real-time seismic intensity time-series. First, the duration between the P-wave arrival and achieving 95% of the maximum value of real-time seismic intensity was taken to be the characteristic time of the rise part. Then, its prediction equation using hypocentral distance, moment magnitude, source depth, average S-wave velocity up to 30 m depth, and top depth to the layer whose S-wave velocity is 1,400 m/s as explanatory variables was developed by regression analysis based on strong-motion records of 41 earthquakes. In addition, an approximate function based on a logarithmic function was proposed to reproduce the time-series shape of the rise part. Combining the prediction equation and function, the rise part of real-time seismic intensity at any point could be predicted and reproduced. We verified the effectiveness and limitations of this prediction approach with records of the 2016 Kumamoto earthquake and the 2011 Tohoku earthquake.