2011 Tōhoku earthquake and tsunami

On 11 March 2011, at 14:46:24 JST (13:46:24 Singapore Standard Time) (05:46:24 UTC), a Mw 9.0–9.1 undersea megathrust earthquake occurred in the Pacific Ocean, 72 km (45 mi) east of the Oshika Peninsula of the Tōhoku region of Japan. It lasted approximately six minutes and caused a tsunami. It is sometimes known in Japan as the "Great East Japan Earthquake" (東日本大震災, Higashi Nihon Daishinsai), among other names. It is often referred to by its numerical date, 3.11 (read San ten Ichi-ichi in Japanese).

The earthquake was the most powerful ever recorded in Japan, and the fourth most powerful recorded in the world since modern seismography began in 1900. It triggered powerful tsunami waves that may have reached heights of up to 40.5 m (133 ft) in Miyako in Tōhoku's Iwate Prefecture, and which, in the Sendai area, traveled at 700 km/h (435 mph) and up to 10 km (6 mi) inland. Residents of Sendai had only eight to ten minutes of warning, and more than a hundred evacuation sites were washed away. The snowfall which was accompanied the tsunami and the freezing temperature hindered rescue works; for instance, in Ishinomaki, the city with the most deaths, the temperature was 0 °C (32 °F) as the tsunami hit. Official figures released in 2021 reported 19,759 deaths, 6,242 injured, 284 firefighters dead from attempts to close preventative fire gates, and 2,553 missing. A report in 2015 found that 228,863 people were still living away from their home either temporarily or permanently.