Separation of Source, Path, and Site Effects based on the Observed Data by K-NET, KiK-net, and JMA Strong Motion Network

Abstract

Adequate evaluation of the strong motion characteristics is indispensable for quantitative strong motion prediction. In this paper, separation of source, path, and site characteristics was carried out by the spectrum separation technique based on the observed data of K-NET, KiK-net, and the JMA Shindo-kei network in Japan. We analyzed 228 sources and 1, 700 sites. As for the source characteristics, we found that among three different types of earthquakes, namely plate boundary, intraplate, and crustal ones, Brune's stress drops are significantly smaller for crustal earthquakes, and that they does not linearly correlate with depth. As for the propagation path effects, we found Q value in the back arc side of a volcanic front to be about one half of the front arc side, and Q for inland earthquakes seems to be equally high as those for plate boundary and intraplate earthquakes.