[S-SS29_28PO1] 地震発生の物理・震源過程

[SSS29-P01] グリッドサーチ法によるMhddの係数決定

*原 辰彦¹ (1.建築研究所国際地震工学センター)

キーワード：マグニチュード, 高周波エネルギー放射, グリッドサーチ法

Hara (2007) developed an empirical magnitude formula using durations of high frequency energy radiation and maximum displacement amplitudes using tele-seismic P waves. Recently, Hara (2013), who referred to this magnitude as M_hdd, tried to re-determine the coefficients of the formula using a larger dataset by a linear inversion. The M_hdd calculated by the proposed coefficients better agree with the moment magnitudes from the Global CMT catalog. However, there is slight epicentral distance dependence for their differences. In this study, in order to reduce this epicentral distance dependence, we performed a grid search to determine the coefficients of M_hdd by minimizing both the differences between M_hdd and moment magnitudes and the dependence of their differences on the epicentral distance. The dataset is the same as that of Hara (2013). The search ranges for each coefficient can be set reasonably based on the studies of Hara (2007) and Hara (2013). The preliminary result suggests that it is possible to reduce the epicentral distance dependence using the coefficients obtained by the grid search method.