Damage to Residential Land and Earth Structures Caused by the 2016 KUMAMOTO Earthquake, JAPAN

Abstract

On 16th of April 2016, the Kumamoto earthquake (Mw 7.0) hit the Central Kyushu Region, Japan, following a Mw 6.2 shock on 14th of April. The earthquake sequences caused severe damage in Kumamoto Prefecture, for example, Kumamoto city, Mashiki Town and Aso Caldera area. This report presents quick reconnaissance results focusing on geotechnical damage features, especially of residential land and earth structures which were observed during field investigations after the main shock. In Mashiki Town, residential houses seem to have been structurally damaged by seismic motion. On the other hand, in a developed land in Aso Caldera area, there were a lot of houses damaged by large deformation of sub soil due to ground motion. The cause of collapse of embankment of Kyushu Highway can be liquefaction of the foundation composed of loosely deposit soil, since the site is located at the old river channel.