Abstract
Many seismographs have been installed in Japan since the 1995 Hyogoken-Nanbu earthquake which brought severe damages to around the city of Kobe. National Research Institute for Earth Science and Disaster Prevention (NIED) deploys digital strong-motion seismographs (KiK-net) all over the country in Japan, which provide vertical array records of ground motions. The total number of observation sites is nearly 700. Data observed by KiK-net can be used to identify the dynamic properties of the subsurface ground. In this study, a new approach is proposed to identify the quality factor, and its problem is discussed.
