The 2011 off the Pacific coast of Tohoku, Japan, earthquake caused serious damage to engineering structures, not only due to tsunamis but also due to strong ground motions. The serious damage of bridge, slope and embankment due to the 2011 main shock is reported. In this study, we computed site amplification factors at seismic observation stations around the damage sites based on the moderate earthquake observation records. The calculated site amplification factors will contribute to the strong motion estimation of the damaged sites and clarification of damage mechanisms in the future study.