Abstract
The strong typhoon Sanba crossed the east side of Japan in September, 2012. The minimum central pressure of the Sanba reached 900 hPa. The typhoon generated wind waves more than 15 m in the significant wave height and gave severe damages to coastal structures. This study analyzed observed wave records at 10 stations along the typhoon track. A series of numerical analysis was performed to understand the characteristics of extreme sea condition by the typhoon. The maximum wave heights were estimated based on the spectral wave model and the nonlinear short wave statistical theory. The observed data shows the nonlinear enhancement of maximum wave height slightly. The estimated maximum wave height by the nonlinear theory shows better agreement with the observed peak of maximum wave height than that by the linear theory.