Damage Statistics from Japanese Earthquakes

摘要

Information derived from discussions during a visit to Japan is presented on two earthquakes which occurred in 1968 and which caused significant shaking of modern tall buildings: the Higashi-Matsuyama earthquake and the Tokachi-Oki earthquake. The Higashi-Matsuyama earthquake had a Richter magnitude of 6.1. Its epicenter was about 50 km from downtown Tokyo, and the focus of the earthquake was at a depth of 70 km. The Tokachi-Oki earthquake had a magnitude of 7.8 and a focal depth of 20 km. The epicenter was off the northeast corner of Honshu. The largest city severely shaken by the earthquake was Hachinobe, about 170 km. from the epicenter. There was no damage to modern tall buildings in Tokyo during the Higashi-Matsuyama earthquake. In Hachinobe and its vicinity there are 16 multi-story buildings: ten having three stories, and two each having four, five, and six stories. Three of the three-story buildings were noted as considerably or heavily damaged. All remaining buildings were described as practically undamaged. The statistics presented are felt to be meaningful with regard to moderate or heavy damage but not necessarily correct with respect to light damage.