2023 年 23 巻 6 号 p. 6_1-6_18
We re-examined the empirical scaling relationship between seismic moment M0 and short-period level A, which is the flat level of the acceleration source spectrum, adopted for setting asperity models of the inland crustal earthquakes in the "Recipe" for predicting strong ground motions published by the Headquarters for Earthquake Research Promotion (2020). Taking into consideration the scaling relationship between seismic moment and rupture area, which is defined as the three-stage model in the Recipe, an empirical equation was newly proposed as a three-fold-line model in which the short-period level was scaled with M01/3, M01/4, and M01/2 for each stage of the three-stage model. By comparing this new empirical equation with the data obtained from earthquake observation records, which included the area and stress drop of the strong motion generation area (SMGA), we found that the three-fold-line model for short-period level could match the short-period level data of SMGAs, and that the stress drop calculated from the empirical equation is independent of the seismic moment, which is consistent with the observational stress drop data of SMGAs.
