On 11 March 2011, at 14:46 JST (05:46 UTC), a 9.0–9.1 undersea megathrust earthquake occurred in the Pacific Ocean, east of the Oshika Peninsula of the Tōhoku region. It lasted approximately six minutes, causing a tsunami. It is sometimes known in Japan as the "Great East Japan Earthquake", among other names. The disaster is often referred to as simply 3.11 (read san ten ichi-ichi in Japanese). It was the most powerful earthquake ever recorded in Japan, and the fourth most powerful earthquake recorded in the world since modern seismography began in 1900. The earthquake triggered powerful tsunami waves that may have reached heights of up to in Miyako in Tōhoku's Iwate Prefecture, and which, in the Sendai area, traveled at and up to 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 accompanied the tsunami and the freezing temperature hindered rescue works greatly; for instance, Ishinomaki, the city with most deaths, was as the tsunami hit. The official figures released in 2021 reported and and a report from 2015 indicated 228,863 people were still living away from their home in either temporary housing or due to permanent relocation. The tsunami caused the Fukushima Daiichi nuclear disaster, primarily the meltdowns of three of its reactors, the discharge of radioactive water in Fukushima and the associated evacuation zones affecting hundreds of thousands of residents. Many electrical generators ran out of fuel. The loss of electrical power halted cooling systems, causing heat to build up. The heat build-up caused the generation of hydrogen gas. Without ventilation, gas accumulated within the upper refueling hall and eventually exploded causing the refueling hall's blast panels to be forcefully ejected from the structure. Residents within a radius of the Fukushima Daiichi Nuclear Power Plant and a radius of the Fukushima Daini Nuclear Power Plant were evacuated. Early estimates placed insured losses from the earthquake alone at US$14.