Abstract
The Matsurube Bridge, which is located near the epicenter of the 2008 Iwate-Miyagi Nairiku, Japan, Earthquake (Mj7.2) collapsed due to the failure of the ground behind the abutment. In order to analyze the collapse mechanism, it is very important to evaluate the strong seismic motion at the bridge site with high accuracy. First of all, aftershock observations and microtremor measurements were carried out at the bridge site in this study. Next, site effects at the left and right bank of the bridge were evaluated based on the aftershock records. Finally, seismic waveforms at the Matsurube Bridge during the 2008 Iwate-Miyagi Nairiku Earthquake were estimated based on empirical site amplification and phase effects. The estimated seismic motions will be useful for a rational safety assessment of a bridge.
