The Yuasa-cho in Wakayama prefecture, which will be one of the most heavily damaged area in the next Nankai earthquake, is selected to consider how to reduce the earthquake damage of traditional wooden houses in the important district of groups of historic buildings. Seismic performance of 10 houses is evaluated based on microtremor measurements and structural characteristics investigation. As results, yield base shear coefficient of large houses with large hanging walls is about 0.2 and such houses may collapse at the maximum shear deformation angle of 1/25.
