Search results
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.
- Overview
- The earthquake and tsunami
The magnitude of the earthquake that caused a devastating tsunami in 2011 was 9.0. The earthquake occurred at 2:46 PM on March 11.
Where was the epicenter of the Great Sendai Earthquake?
The 2011 earthquake's epicenter was located some 80 miles (130 km) east of Sendai, Miyagi prefecture, and the focus occurred 18.6 miles (about 30 km) below the floor of the western Pacific Ocean.
What was the death toll of the earthquake and tsunami that struck Japan in 2011?
The official total for the number of those confirmed dead or listed as missing from the 2011 disaster was about 18,500. Other estimates gave a final toll of at least 20,000. The great majority of those killed were drowning victims of the tsunami waves.
What effects did the Japan earthquake and tsunami of 2011 have?
The magnitude-9.0 earthquake struck at 2:46 pm. (The early estimate of magnitude 8.9 was later revised upward.) The epicentre was located some 80 miles (130 km) east of the city of Sendai, Miyagi prefecture, and the focus occurred at a depth of 18.6 miles (about 30 km) below the floor of the western Pacific Ocean. The earthquake was caused by the rupture of a stretch of the subduction zone associated with the Japan Trench, which separates the Eurasian Plate from the subducting Pacific Plate. (Some geologists argue that this portion of the Eurasian Plate is actually a fragment of the North American Plate called the Okhotsk microplate.) A part of the subduction zone measuring approximately 190 miles (300 km) long by 95 miles (150 km) wide lurched as much as 164 feet (50 metres) to the east-southeast and thrust upward about 33 feet (10 metres). The March 11 temblor was felt as far away as Petropavlovsk-Kamchatsky, Russia; Kao-hsiung, Taiwan; and Beijing, China. It was preceded by several foreshocks, including a magnitude-7.2 event centred approximately 25 miles (40 km) away from the epicentre of the main quake. Hundreds of aftershocks, dozens of magnitude 6.0 or greater and two of magnitude 7.0 or greater, followed in the days and weeks after the main quake. (Nearly two years later, on December 7, 2012, a magnitude-7.3 tremor originated from the same plate boundary region. The quake caused no injuries and little damage.) The March 11, 2011, earthquake was the strongest to strike the region since the beginning of record keeping in the late 19th century, and it is considered one of the most powerful earthquakes ever recorded. It was later reported that a satellite orbiting at the outer edge of Earth’s atmosphere that day had detected infrasonics (very low-frequency sound waves) from the quake.
The sudden horizontal and vertical thrusting of the Pacific Plate, which has been slowly advancing under the Eurasian Plate near Japan, displaced the water above and spawned a series of highly destructive tsunami waves. A wave measuring some 33 feet high inundated the coast and flooded parts of the city of Sendai, including its airport and the surrounding countryside. According to some reports, one wave penetrated some 6 miles (10 km) inland after causing the Natori River, which separates Sendai from the city of Natori to the south, to overflow. Damaging tsunami waves struck the coasts of Iwate prefecture, just north of Miyagi prefecture, and Fukushima, Ibaraki, and Chiba, the prefectures extending along the Pacific coast south of Miyagi. In addition to Sendai, other communities hard-hit by the tsunami included Kamaishi and Miyako in Iwate; Ishinomaki, Kesennuma, and Shiogama in Miyagi; and Kitaibaraki and Hitachinaka in Ibaraki. As the floodwaters retreated back to the sea, they carried with them enormous quantities of debris, as well as thousands of victims caught in the deluge. Large stretches of land were left submerged under seawater, particularly in lower-lying areas.
The earthquake triggered tsunami warnings throughout the Pacific basin. The tsunami raced outward from the epicentre at speeds that approached about 500 miles (800 km) per hour. It generated waves 11 to 12 feet (3.3 to 3.6 metres) high along the coasts of Kauai and Hawaii in the Hawaiian Islands chain and 5-foot (1.5-metre) waves along the island of Shemya in the Aleutian Islands chain. Several hours later 9-foot (2.7-metre) tsunami waves struck the coasts of California and Oregon in North America. Finally, some 18 hours after the quake, waves roughly 1 foot (0.3 metre) high reached the coast of Antarctica and caused a portion of the Sulzberger Ice Shelf to break off its outer edge.
Britannica Quiz
The proximate cause of the accident was the 2011 Tōhoku earthquake and tsunami, which resulted in electrical grid failure and damaged nearly all of the power plant's backup energy sources.
5 days ago · Fukushima accident, disaster that occurred in 2011 at the Fukushima Daiichi (‘Number One’) nuclear power plant on the Pacific coast of northern Japan, which was caused by a severe earthquake and powerful series of tsunami waves and was the second worst nuclear power accident in history.
- The Editors of Encyclopaedia Britannica
- The Fukushima accident was an accident in 2011 at the Fukushima Daiichi (“Number One”) nuclear power plant in Japan. It is the second worst nuclear...
- An earthquake and tsunami led to power loss in the Fukushima Daiichi plant. Without power, the cooling systems failed in three reactors, and their...
- Immediately after the Fukushima accident in 2011, radiation levels increased in food, water, and the ocean near the Fukushima Daiichi plant. Becaus...
- Nobody died as a direct result of the Fukushima nuclear disaster. However, in 2018 one worker in charge of measuring radiation at the plant died of...
Aug 23, 2023 · It triggered a tsunami which swept over Japan's main island of Honshu, killing more than 18,000 people and wiping entire towns off the map. At the Fukushima nuclear power plant, the gigantic...
Jun 13, 2011 · June 9, 2011 — The March 11 earthquake and tsunami left more than 28,000 dead or missing. See incredible footage of the tsunami swamping cities and turning buildings into rubble. Subscribe:...
- 4 min
- 93M
- National Geographic
Updated Monday, 29 April 2024. Following a major earthquake, a 15-metre tsunami disabled the power supply and cooling of three Fukushima Daiichi reactors, causing a nuclear accident beginning on 11 March 2011. All three cores largely melted in the first three days.
