Short-Period Spectral Level of the 1948 Fukui and 1945 Mikawa Earthquakes Based on Seismic Intensity Using the Empirical Green's Function Method

Abstract

Short-period period spectral levels of the 1948 Fukui earthquake (M_J 7.1), which was a buried strike-slip fault, and the 1945 Mikawa earthquake (M_J 6.8), which was a reverse fault with a 28 km-long surface rupture were estimated using the empirical Green's function method to match the JMA seismic intensity scales. Based on the strong-motion prediction recipe, we calculated the areas of outerfaults and the strong-motion generation areas. Then we did grid search calculation to get best location of strong-motion generation areas and best value of the short-period spectral level by changing 0.1 increments centered on the level by Dan et al.'s relation (2001). As a result, the short-period spectral levels of the Fukui and Mikawa earthquakes were estimated to be 0.7 to 0.8 times and 0.5 to 0.6 times that of by Dan et al.' relation, respectively.