Study on toppled vehicles in the 2016 Kumamoto earthquake, Japan

Abstract

Kumamoto earthquake M7.3 hit southern Japan on April 16, 2016. Extensive damages on structures were concentrated in the areas where the rupture exposed to the surface. We found many vehicles toppled on the site during damage survey in Tateno and Kurokawa area. Seismic response analyses of car are executed to find out the scenario of toppling condition. Relationship of lateral peak ground acceleration (PGA) associated with toppling under several conditions are presented. Relationship of amplitude of vertical component, dominant frequency of the input wave and phase difference of lateral to the vertical wave are presented and formulated as ground motion characteristics of the earthquake. Cars toppled during Kumamoto earthquake were analyzed using the seed ground motion recorded in KMMH16, NIED K-Net station in Mashiki town, data available nearby of the epicenter, having the highest PGA. Suzuki Every Wagon was selected for analysis. The car got toppled when the PGA is 14.17 m/sec2 in 10.86 seconds as scaling factor is 2.654 for lateral component, keeping the vertical components unchanged.