What is the maximum run-up height of the 2011 Tohoku tsunami in Japan?
Answer
40.5 meters
The maximum reported run-up height of the 2011 Tōhoku tsunami in Japan was 40.5 metres. This extreme height was recorded in Miyako, Iwate Prefecture, where the wave climbed far above the normal shoreline as it moved inland.
The tsunami followed a magnitude 9.0–9.1 megathrust earthquake on 11 March 2011. The earthquake lifted and displaced the seafloor across a huge area, sending waves throughout the Pacific. Along Japan’s northeastern coast, bays and narrow inlets focused the water and amplified its height.
Measurements vary slightly because researchers distinguish between observed wave height, inundation depth and run-up elevation. Ryōri Bay, near Ōfunato, recorded a measured height of about 40.1 metres, while 40.5 metres is commonly cited as the maximum estimated run-up. The disaster killed nearly 20,000 people and triggered the Fukushima Daiichi nuclear accident.