摘要：Japan"s first open sea offshore wind farm, Kamisu offshore windfarm Phase 1, was stricken by an earthquake of intensity 6 on the Japanese seismic scale and a five-meter-high tsunami during the Great East Japan Earthquake on March 11, 2011. The wind farm resumed operation on March 14 after checks revealed no damage to the system, even though the wind farm was temporarily forced to stop due to the grid failure caused by the earthquake. Wind turbines require a precise seismic design especially in an earthquake-prone country such as Japan. Wind power Kamisu Phase 2 was built one year after the earthquake based on the experience of Kamisu Phase 1. This paper presents the seismic design of offshore wind turbines and the situation during the earthquake and tsunami.