Grand surface deformations along the Otuki fault at the 1995 Hyogoken-nanbu earthquake

Abstract

We have investigated the distribution and properties of the ground surface deformations, which were caused by the Hyogoken-nanbu earthquake, in the southeastern area of the Rokko Mountains, eastern part of Kobe city in Japan. The landforms of the study area are characterized by foot of Rokko Mountains formed by the weathered granitic rocks. The Otuki fault in this area is running parallel to the mountain foot from NE to SW. The ground surface deformations appear to be concentrated along the Otuki fault. Many mountain slope failures were collapsed on the Otuki fault. The reason for these slope failures distribution are thought to be strong ground motion by Hyogoken-nanbu earthquake. The upper parts of the mountain slope failures have broken by tension fractures of NE-SW.