ポアソン確率に基づく地震活動表現方法の検証

The characteristics of eMAP (evaluation Method of Appearance Probability), a method for visualizing seismic rate changes (SRCs) based on Poisson probability, were discussed in comparison with Matsumura’s method and ZMAP. For SRCs made by the changes in the magnitude scale of seismic events (ΔM), from －0.5 to ＋0.5 in the Richter scale, the analytical values of Matsumura’s method and ZMAP showed almost linear changes, while those of eMAP were particularly sensitive to changes in ΔM from about －0.3 to ＋0.3 and saturated to 1 or 0 for further increases or decreases in ΔM. As for the spatial distribution of quiescence and activation in SRC given in a grid of 50 km spacing, Matsumura’s method and ZMAP did not have high resolution due to spatial fluctuation of SRCs generated naturally. In contrast to these, eMAP showed the best resolution due to its robustness to the SRC fluctuation.