The Japan Society of Civil Engineers proposed to introduce the earthquake motion of level 2 to reflect the seismic forces of the Great Hanshin-Awaji Earthquake in 1995. After the Great East Japan Earthquake in 2011, the undertaking of "human based" soft measures for evacuation in the case of tsunamis that exceed the conventionally assumed scale of level 1 was discussed; design methods that allow facilities to withstand tsunamis in addition to conventional seismic forces are in demand. The level

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... 2 disasters experienced in Japan were incorporated into design concepts only after such large disasters occurred. However, actual level 2 disasters include events other than earthquakes and tsunamis. Increasing seawater temperature due to global warming will induce sea level rise, and typhoons will likely become larger in scale. Disastrous events that exceed conventional design conditions in high tides are more likely to occur. The three largest bay regions in Japan, where large hinterlands lie below sea level, require examination to clarify these risks. The authors reviewed various phenomena and present that risk management on the basis of level 2 disaster risks is of great importance.