Chapter 13 - Estimation of the Current Risk to Human Damage Life Posed by Future Tsunamis in Japan

Abstract

On the 11th of March 2011 an earthquake offshore the northeast coast of Japan generated a huge tsunami which overwhelmed coastal defences and inundated extensive areas of the Tohoku coastline. Japan was considered to be well prepared against such disasters but nevertheless casualties were high, though death rates were not homogeneous within the affected regions. In the present paper the authors investigate the relationship between human damage, maximum tsunami wave height and arrival time during the 2011 Tohoku Earthquake Tsunami. Generally speaking, the results indicate a positive correlation between the casualty rates inside inundated coastal settlements and tsunami height and a negative one regarding the arrival time (i.e. longer arrival times allowed residents more time to successfully evacuate). Based on these results a new tsunami category is introduced to clarify the potential threat that various earthquake scenarios pose to coastal communities in the Kanto area in Japan. These results contain useful insights for managing risks and prioritizing the investment in tsunami countermeasures to reduce future human suffering due to these disasters.