松代地震の地割れ群について

概要

論文の詳細を見る
Fissures caused by Matsushiro earthquake in 1965 are divided into two types. One is creeping landslides, and the other is connected with the fault. The former is visible in the following areas: Nuruyu in Wakaho town, Nagai and Nagare in Matsushiro town Nagano City and Kuiishi, Kosnoku City. Intervals of the above area all in 8-10 km. The line linking these areas running with the direction of NNE-SSW, nearly parallel with the one of tectonic line in these areas. And it also coincides with the one of the long axis of the oval form, evolving epicenter's distribution. The latter is found in the areas such as Hannyaji, Takehara and Sezeki in Matsumoto town. The number of fissures in each area is several, following closely after with the direction of EW. They run in a zone of the direction of N60W, whose width is 200 m and length is 2.4 km. It is supposed that this zone is a stress one suffered pressure with a direction of EW. Considdering from the existence of left lateral sliding fissures, the writer suposed that the stress zone were made by the same movement of dormant fault. The direction of it coincides with the sort axis of clipsoid area of epicenter's distribution. These two directions of fissures almost harmonize with the main lectonic direction prevailing in the northern Fossa Magna.
1969-05-25