Simplified evaluation method of equivalent S-wave velocity of partial improved ground is presented in this paper. Equivalent S-wave velocity, which is calculated by the homogenization method, is simply determined by the shape of the improvement, replacement ratio and S-wave velocity ratio of the improvement and soil. The reliability of the equivalent velocity by the method is evaluated by the S-wave velocity profiles estimated using the microtremors array measurements in a field. Good agreements with measurement and calculated S-wave velocity suggest that the developed method is useful of estimation of equivalent S-wave velocity of partial improved ground.
