The 2016 Fukushima earthquake and tsunami: Local tsunami behavior and recommendations for tsunami disaster risk reduction

Abstract The 2016 Fukushima earthquake and tsunami presented several new issues of tsunami generation mechanism and propagation, as well as of organizational responses such as evacuation procedures and dissemination of tsunami warning. This study focuses on explanations to issues of public interest based on the experiences during the 2016 tsunami: (1) Despite Fukushima Prefecture's proximity to the earthquake's epicenter, why was the largest wave observed in the neighboring Miyagi Prefecture? (2) Why was the second wave of the tsunami larger than the first? (3) Why was the tsunami advisory elevated to a tsunami warning in Miyagi Prefecture? (4) Why did tsunami intrusions into rivers occur? (5) And why were local tsunami runup values much higher than the broadcasted tsunami amplitudes from local tide gauges? In the wake of the 2011 Great East Japan earthquake and tsunami, this study also points out remaining problems and new perspectives related to tsunami disaster risk reduction. These include tsunami warnings and advisories by emergency management agencies, the fact that tsunami waves are higher near the coast than in the open ocean, and refraining from being close to rivers in case of a tsunami. Based to Japan's experiences with disaster mitigation, lessons were learned from numerous events that could lead to revisions and improvements of current warning systems and provide useful guidelines for other countries.