波線追跡法によるLove波伝播経路の推定

抄録

During the 1984 Nagano-ken-seibu earthquake, a rather-long period significant later phase due to Love-waves appeared after one minute from the principal groumd motion at the Kumagaya JMA station. In order to estimate the paths of these Love-waves, the ray tracing method is applied and two paths from the western part of Nagano prefecture to Kumagaya were estimated. One reaches Kumagaya directly and the other from NW direction through a narrow sedimentary valley. It's also attempted to predict the earthquakes which will make Love-waves propagate to Kumagaya. There are two paths oriented by the sedimentary valley, and they reach the western part of Nagano prefecture and the south off Kanto district.