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105-667: The Fukushima Daiichi Nuclear Power Plant ( 福島第一原子力発電所 , Fukushima Daiichi Genshiryoku Hatsudensho , Fukushima number 1 nuclear power plant) is a disabled nuclear power plant located on a 3.5-square-kilometre (860-acre) site in the towns of Ōkuma and Futaba in Fukushima Prefecture , Japan. The plant suffered major damage from the magnitude 9.1 earthquake and tsunami that hit Japan on March 11, 2011. The chain of events caused radiation leaks and permanently damaged several of its reactors, making them impossible to restart. The working reactors were not restarted after

210-769: A M w  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 . 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. The disaster is often referred to by its numerical date, 3.11 (read san ten ichi-ichi in Japanese). It

315-519: A 7.7 M w quake at 15:26 all occurred on 11 March. A month later, a major aftershock struck offshore on 7 April with a magnitude of 7.1 M w . Its epicenter was underwater, 66 km (41 mi) off the coast of Sendai. The Japan Meteorological Agency assigned a magnitude of 7.4 M JMA , while the United States Geological Survey lowered it to 7.1 M w . At least four people were killed, and electricity

420-498: A Mark II type (over/under) containment structure. Unit 1 is a 460 MWe boiling water reactor ( BWR-3 ) constructed in July 1967. It commenced commercial electrical production on March 26, 1971, and was initially scheduled for shutdown in early 2011. In February 2011, Japanese regulators granted an extension of ten years for the continued operation of the reactor. It was damaged during the 2011 Tōhoku earthquake and tsunami . Unit 1

525-455: A certain magnitude (magnitude 8 on the JMA scale); that is, in the case of very large earthquakes, the scales' values change little despite large differences in the earthquakes' energy. This resulted in an underestimation of the tsunami's height in initial reports. Problems in issuing updates also contributed to delays in evacuations. The warning system was supposed to be updated about 15 minutes after

630-533: 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 the most deaths, was 0 °C (32 °F) as the tsunami hit. The official figures released in 2021 reported 19,759 deaths, 6,242 injured, and 2,553 people missing, 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

735-520: A magnitude of at least 8.4 M w , which also created a large tsunami that inundated the Sendai plain. Three tsunami deposits have been identified within the Holocene sequence of the plain, all formed within the last 3,000 years, suggesting an 800 to 1,100 year recurrence interval for large tsunamigenic earthquakes. In 2001 it was reckoned that there was a high likelihood of a large tsunami hitting

840-597: A possible uncovering of the Spent fuel pools in Units 1, 3 and 4. Units 5 & 6 were reported on March 19, by the station-wide alert log updates of the IAEA , to have gradually rising spent fuel pool temperatures as they had likewise lost offsite power, but onsite power provided by Unit 6's two diesel generators that had not been flooded, were configured to do double-duty and cool both Unit 5 and 6's spent fuel pools "and cores". As

945-438: A precautionary measure, vents in the roofs of these two units were also made to prevent the possibility of hydrogen gas pressurization and then ignition. Radiation releases from Units 1–4 forced the evacuation of 83,000 residents from towns around the plant. The triple meltdown also caused concerns about contamination of food and water supplies, including the 2011 rice harvest, and also the health effects of radiation on workers at

1050-535: A result of the quake. The report also stated that the quake had caused several major landslides on the seabed in the affected area. The Earth's axis shifted by estimates of between 10 and 25 cm (4 and 10 in). This deviation led to a number of small planetary changes, including the length of a day , the tilt of the Earth , and the Chandler wobble . The speed of the Earth's rotation increased, shortening

1155-733: A small piece of melted fuel from Fukushima's reactor for radiation testing, a key step in its complex decommissioning process. Daiichi The phrase is also written without the hyphen, as daiichi . Dai-ichi is frequently used in proper names , hence capitalized; also Dai-Ichi and occasionally Dai Ichi . There is a sound-alike common first name with different spelling. Dai-ni (第二) means number two or second , using two parallel bars (二) or "2" for "ni"; also daini Dai-san (第三) means number three or third , using three parallel bars (三) or "3" for "san" And continuing for 4, 5, 6, etc. 2011 T%C5%8Dhoku earthquake and tsunami On 11 March 2011, at 14:46 JST (05:46 UTC ),

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1260-501: A small sample of melted radioactive fuel from a damaged reactor. The sample will help improve future decommissioning strategies, though doubts persist about the long-term cleanup timeline. A glitch halted Telesco, the robot attempting to retrieve the sample, further delaying the mission. Concerns also remain over the impact on marine life as radioactive water is being released into the Pacific Ocean, despite government assurances that it meets safety standards. In November 2024,TEPCO has moved

1365-478: A small tsunami was recorded after a 7.1 M w aftershock. As of 16 March 2012 aftershocks continued, totaling 1887 events over magnitude 4.0; a regularly updated map showing all shocks of magnitude 4.5 and above near or off the east coast of Honshu in the last seven days showed over 20 events. As of 11 March 2016 there had been 869 aftershocks of 5.0 M w or greater, 118 of 6.0 M w or greater, and 9 over 7.0 M w as reported by

1470-667: A time for safety checks due to the TEPCO data falsification scandal . On February 28, 2011, TEPCO submitted a report to the Japanese Nuclear and Industrial Safety Agency admitting that the company had previously submitted fake inspection and repair reports. The report revealed that TEPCO failed to inspect more than 30 technical components of the six reactors, including power boards for the reactor's temperature control valves, as well as components of cooling systems such as water pump motors and emergency power diesel generators. In 2008,

1575-467: A timely warning, the initial earthquake and tsunami warning that was issued for the event was based on a calculation that requires only about three minutes. This calculation is, in turn, based on the maximum amplitude of the seismic wave. The amplitude of the seismic wave is measured using the JMA magnitude scale , which is similar to Richter scale . However, these scales "saturate" for earthquakes that are above

1680-399: A total area of approximately 561 square kilometers (217 sq mi) in Japan. The earthquake took place at 14:46 JST (UTC 05:46) around 67 kilometers (42 mi) from the nearest point on Japan's coastline, and initial estimates indicated the tsunami would have taken 10 to 30 minutes to reach the areas first affected, and then areas farther north and south based on the geography of

1785-401: A tsunami warning, data from GPS tidal meters as well as from undersea water pressure meters, and there are plans to install more of these meters and to develop further technology to utilize data observed by them. To prevent under-reporting of tsunami heights, early quantitative observation data that are smaller than the expected amplitude will be overridden and the public will instead be told that

1890-496: A width of 200 km (120 mi). Analysis showed that this earthquake consisted of a set of three events. Other major earthquakes with tsunamis struck the Sanriku Coast region in 1896 and in 1933 . The source area of this earthquake has a relatively high coupling coefficient surrounded by areas of relatively low coupling coefficients in the west, north, and south. From the averaged coupling coefficient of 0.5–0.8 in

1995-542: Is believed that the early warning by the Japan Meteorological Agency (JMA) saved many lives. The warning for the general public was delivered about eight seconds after the first P wave was detected, or about 31 seconds after the earthquake occurred. However, the estimated intensities were smaller than the actual ones in some places, especially in Kanto, Koshinetsu , and Northern Tōhoku regions where

2100-523: Is deemed the record in Japan historically, as of reporting date, that exceeds 38.2 meters (125 ft) from the 1896 Sanriku earthquake . It was also estimated that the tsunami reached heights of up to 40.5 meters (133 ft) in Miyako in Tōhoku's Iwate Prefecture. The inundated areas closely matched those of the 869 Sanriku tsunami . Inundation heights were observed along 2,000 kilometers (1,200 mi) of

2205-682: Is estimated at $ 71 billion. TEPCO will shoulder $ 143 billion of decommissioning and decontamination, while the Ministry of Finance of Japan will provide $ 17 billion. Other power companies will also contribute to the cost. On September 26, 2020, Prime Minister Yoshihide Suga visited the Daiichi Nuclear Power Plant to show that his cabinet prioritized the reconstruction of areas that were affected by natural and nuclear disasters. The three reactors host 880 tonnes of highly radioactive melted nuclear fuel. As of 2024–13 years after

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2310-575: 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

2415-521: The moment magnitude scale occurred at 14:46 Japan Standard Time (JST) off the northeast coast of Japan, one of the most powerful earthquakes in history. Units 4, 5 and 6 had been "shut down" prior to the earthquake for planned maintenance. The remaining reactors were shut down/ SCRAMed automatically after the earthquake, and the remaining decay heat of the fuel was being cooled with power from emergency generators. The subsequent destructive tsunami with waves of up to 14 metres (46 ft) that over-topped

2520-544: The 2004 Indian Ocean quake. Japan's National Research Institute for Earth Science and Disaster Prevention (NIED) calculated a peak ground acceleration of 2.99  g (29.33 m/s ). The largest individual recording in Japan was 2.7  g , in Miyagi Prefecture, 75 km from the epicenter; the highest reading in the Tokyo metropolitan area was 0.16  g . The strong ground motion registered at

2625-493: The Earthquake Early Warning system and the actual intensities occurred in the aftershocks and triggered earthquakes. Such discrepancies in the warning were attributed by the JMA to the system's inability to distinguish between two different earthquakes that happened at around same time, as well as to the reduced number of reporting seismometers due to power outages and connection failures. The system's software

2730-535: The Fukushima Daiichi nuclear power plant and to cancel plans to build units 7 and 8. It refused however to make a decision regarding units 5 and 6 of the station or units 1 to 4 of the Fukushima Daini nuclear power station until a detailed investigation is made. In December 2013 TEPCO decided to decommission the undamaged units 5 and 6; they may be used to test remote clean-up methods before use on

2835-595: The Fukushima Daini plant by the Tomioka Line (富岡線). Its major connection to the north is the Iwaki Line (いわき幹線), which is owned by Tohoku Electric Power . It has two connections to the south-west that connect it to the Shin-Iwaki substation (新いわき). The plant reactors came online one at a time beginning in 1970 and the last in 1979. From the end of 2002 through 2005, the reactors were among those shut down for

2940-550: The Fukushima disaster and the Chernobyl disaster worldwide the only Level 7 events up to date. Japanese wheelchair basketball player Akira Toyoshima revealed that he was working as an accountant at the Fukushima Daiichi Nuclear Power Plant when the 2011 Tōhoku earthquake and tsunami struck Japan and the tsunami eventually claimed the lives of thousands of people. Toyoshima insisted that he

3045-557: The IAEA warned Japan that the Fukushima plant was built using outdated safety guidelines, and could be a "serious problem" during a large earthquake. The warning led to the building of an emergency response center in 2010, used during the response to the 2011 nuclear accident. On April 5, 2011, TEPCO vice president Takashi Fujimoto announced that the company was canceling plans to build Reactors No. 7 and 8. On May 20 TEPCO's board of directors' officially voted to decommission Units 1 through 4 of

3150-399: The JMA bulletin also included the caveat that "At some parts of the coasts, tsunamis may be higher than those observed at the observation sites." The timing of the earliest recorded tsunami maximum readings ranged from 15:12 to 15:21, between 26 and 35 minutes after the earthquake had struck. The bulletin also included initial tsunami observation details, as well as more detailed maps for

3255-427: The JMA magnitude scale to saturate, no quantitative prediction will be released in the initial warning; instead, there will be words that describe the situation's emergency. There are plans to install new teleseismometers with the ability to measure larger earthquakes, which would allow the calculation of a quake's moment magnitude scale in a timely manner. JMA also implemented a simpler empirical method to integrate, into

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3360-576: The Japanese Meteorological Agency. The number of aftershocks was associated with decreased health across Japan. On 13 February 2021, a magnitude 7.1–7.3 earthquake struck off the coast of Sendai. It caused some damage in Miyagi and Fukushima prefectures. One person was killed, and 185 were injured. The Geospatial Information Authority of Japan reported land subsidence based on the height of triangulation stations in

3465-706: The Japanese coast guard said that the quake shifted the seabed near the epicenter 24 meters (79 ft) and elevated the seabed off the coast of Miyagi Prefecture by 3 meters (9.8 ft). A report by the Japan Agency for Marine-Earth Science and Technology , published in Science on 2 December 2011, concluded that the seabed in the area between the epicenter and the Japan Trench moved 50 meters (160 ft) east-southeast and rose about 7 meters (23 ft) as

3570-432: The Japanese government approved the discharge of radioactive water , which has been treated to remove radionuclides other than tritium , into the Pacific Ocean over the course of 30 years. The reactors for Units 1, 2, and 6 were supplied by General Electric , those for Units 3 and 5 by Toshiba , and Unit 4 by Hitachi . All six reactors were designed by General Electric. Architectural design for General Electric's units

3675-457: The Pacific Ocean region reaching the entire Pacific coast of North and South America from Alaska to Chile . Warnings were issued and evacuations were carried out in many countries bordering the Pacific. Although the tsunami affected many of these places, the heights of the waves were minor. Chile's Pacific coast, one of the farthest from Japan at about 17,000 kilometers (11,000 mi) away,

3780-547: The Sendai plain as more than 1,100 years had then elapsed. In 2007, the probability of an earthquake with a magnitude of M w 8.1–8.3 was estimated as 99% within the following 30 years. This earthquake occurred where the Pacific plate is subducting under the plate beneath northern Honshu. The Pacific plate, which moves at a rate of 8 to 9 cm (3.1 to 3.5 in) per year, dips under Honshu's underlying plate, building large amounts of elastic energy . This motion pushes

3885-500: The USGS further upgraded the earthquake to 9.1. Sendai was the nearest major city to the earthquake, 130 km (81 mi) from the epicenter; the earthquake occurred 373 km (232 mi) northeast of Tokyo . The main earthquake was preceded by a number of large foreshocks , with hundreds of aftershocks reported. One of the first major foreshocks was a 7.2 M w event on 9 March, approximately 40 km (25 mi) from

3990-453: The accident—attempts to remove highly radioactive material from the damaged reactor were halted. Tesco attempted to remove 3 grams (0.1 ounce) from an estimated 880 tons of lethally radioactive molten fuel. This sample will provide critical data for the development of future decommissioning methods, as well as the necessary technology and robots, according to experts. On 11 September 2024, a robotic mission at Fukushima Daiichi restarted to collect

4095-401: The accumulated energy. In the area near the trench, the coupling coefficient is high, which could act as the source of the large tsunami. Most of the foreshocks are interplate earthquakes with thrust-type focal mechanisms. Both interplate and intraplate earthquakes appeared in the aftershocks offshore Sanriku coast with considerable proportions. The surface energy of the seismic waves from

4200-520: The area measured by GPS as compared to their previous values from 14 April 2011. Scientists say that the subsidence is permanent. As a result, the communities in question are now more susceptible to flooding during high tides. One minute before the earthquake was felt in Tokyo, the Earthquake Early Warning system, which includes more than 1,000 seismometers in Japan, sent out warnings of impending strong shaking to millions. It

4305-468: The area of the Honshu rupture is not very straight, it is unusual for the magnitude of its earthquake to exceed 8.5 M w. The hypocentral region of this earthquake extended from offshore Iwate Prefecture to offshore Ibaraki Prefecture . The Japanese Meteorological Agency said that the earthquake may have ruptured the fault zone from Iwate to Ibaraki with a length of 500 km (310 mi) and

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4410-495: The banking system on 14 March 2011 in an effort to normalize market conditions. The estimated economic damages amounted to over $ 300 billion, making it the costliest natural disaster in history . According to a 2020 study, "the earthquake and its aftermaths resulted in a 0.47 percentage point decline in Japan's real GDP growth in the year following the disaster." The magnitude 9.1 ( M w ) undersea megathrust earthquake occurred on 11 March 2011 at 14:46 JST (05:46 UTC) in

4515-518: The coast from Hokkaido to Kyushu in a 2012 study. Maximum run-up heights greater than 10 meters (33 ft) were distributed along 530 kilometers (330 mi) of coast, and maximum run-up heights greater than 20 meters (66 ft) were distributed along 200 kilometers (120 mi) of the coast, measured directly. The tsunami resulted in significant erosion of the Rikuzen-Takata coastline, mainly caused by backwash. A 2016 study indicated that

4620-461: The coast has not naturally recovered at a desirable rate since the tsunami. A Japanese government study found that 58% of people in coastal areas in Iwate, Miyagi, and Fukushima prefectures heeded tsunami warnings immediately after the quake and headed for higher ground. Of those who attempted to evacuate after hearing the warning, only five percent were caught in the tsunami. Of those who did not heed

4725-531: The coastline. At 15:55 JST, a tsunami was observed flooding Sendai Airport , which is located near the coast of Miyagi Prefecture , with waves sweeping away cars and planes and flooding various buildings as they traveled inland. The impact of the tsunami in and around Sendai Airport was filmed by an NHK News helicopter, showing a number of vehicles on local roads trying to escape the approaching wave and being engulfed by it. A 4-meter-high (13 ft) tsunami hit Iwate Prefecture . Wakabayashi Ward in Sendai

4830-428: The coastlines affected by the tsunami waves. JMA also reported offshore tsunami height recorded by telemetry from moored GPS wave-height meter buoys as follows: On 25 March 2011, Port and Airport Research Institute (PARI) reported tsunami height by visiting the port sites as follows: The tsunami at Ryōri Bay ( 綾里湾 ), Ōfunato reached a height of 40.1 meters (132 ft) (run-up elevation). Fishing equipment

4935-460: The creation of a structure to develop the technologies and processes necessary to dismantle the four reactors damaged in the Fukushima accident. To reduce the flow of contaminated water into the Pacific Ocean, TEPCO spent ¥34.5 billion (approx. $ 324 million) to build a 1.5 kilometer-long underground wall of frozen soil around the plant, constructed by Kajima Corporation. 1,500 one-hundred-foot long (thirty-metre), supercooled pipes were inserted into

5040-399: The critical parts of the reactor was discovered. The design basis for tsunamis was 5.7 metres (18 ft 8 in). The reactor's emergency diesel generators and DC batteries, crucial components in helping keep the reactors cool in the event of a power loss, were located in the basements of the reactor turbine buildings. The reactor design plans provided by General Electric specified placing

5145-508: The damaged reactors. In 1990, the U.S. Nuclear Regulatory Commission (NRC) ranked the failure of the emergency electricity generators and subsequent failure of the cooling systems of plants in seismically very active regions one of the most likely risks. The Japanese Nuclear and Industrial Safety Agency (NISA) cited this report in 2004. According to Jun Tateno, a former NISA scientist, TEPCO did not react to these warnings and did not respond with any measures. Filmmaker Adam Curtis mentioned

5250-476: The day by 1.8 microseconds due to the redistribution of Earth's mass. The axial shift was caused by the redistribution of mass on the Earth's surface, which changed the planet's moment of inertia . Because of conservation of angular momentum , such changes of inertia result in small changes to the Earth's rate of rotation. These are expected changes for an earthquake of this magnitude. The earthquake also generated infrasound waves detected by perturbations in

5355-505: The earthquake caused such a dramatic change in the Earth's rotation came from the United States Geological Survey which monitors Global Positioning Satellite (GPS) stations across the world. The Survey team had several GPS monitors located near the scene of the earthquake. The GPS station located nearest the epicenter moved almost 4 m (13 ft). This motivated government researchers to look into other ways

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5460-497: The earthquake may have had large scale effects on the planet. Calculations at NASA's Jet Propulsion Laboratory determined that the Earth's rotation was changed by the earthquake to the point where the days are now 1.8 microseconds shorter. Japan experienced over 1,000 aftershocks since the earthquake, with 80 registering over magnitude 6.0 M w and several of which have been over magnitude 7.0 M w . A magnitude 7.4 M w at 15:08 (JST), 7.9 M w at 15:15 and

5565-401: The earthquake occurred, by which time the calculation for the moment magnitude scale would normally be completed. However, the strong quake had exceeded the measurement limit of all of the teleseismometers within Japan, and thus it was impossible to calculate the moment magnitude based on data from those seismometers. Another cause of delayed evacuations was the release of the second update on

5670-441: The earthquake was calculated to be 1.9×10 joules , which is nearly double that of the 9.1 M w 2004 Indian Ocean earthquake and tsunami that killed 230,000 people. If harnessed, the seismic energy from this earthquake would power a city the size of Los Angeles for an entire year. The seismic moment (M 0 ), which represents a physical size for the event, was calculated by the USGS at 3.9×10 joules, slightly less than

5775-431: The epicenter experienced the largest shifts. A 400-kilometer (250 mi) stretch of coastline dropped vertically by 0.6 meters (2 ft 0 in), allowing the tsunami to travel farther and faster onto land. One early estimate suggested that the Pacific plate may have moved westward by up to 20 meters (66 ft), and another early estimate put the amount of slippage at as much as 40 m (130 ft). On 6 April,

5880-471: The epicenter of the 11 March earthquake, with another three on the same day in excess of 6.0 M w . Following the main earthquake on 11 March, a 7.4 M w aftershock was reported at 15:08 JST (6:06 UTC), succeeded by a 7.9 M w at 15:15 JST (6:16 UTC) and a 7.7 M w at 15:26 JST (6:26 UTC). Over 800 aftershocks of magnitude 4.5 M w or greater occurred after the initial quake. Aftershocks followed Omori's law , which states that

5985-527: The events. First commissioned in 1971, the plant consists of six boiling water reactors . These light water reactors drove electrical generators with a combined power of 4.7 GWe, making Fukushima Daiichi one of the 15 largest nuclear power stations in the world . Fukushima was the first nuclear plant to be designed, constructed, and run in conjunction with General Electric and Tokyo Electric Power Company (TEPCO). The sister nuclear plant Fukushima Daini ( "number two" ), 12 km (7.5 mi) to

6090-589: The fact that they were still included in the supply plan for 2011, released in March 2011, after the accidents. The company stated that the plan had been drafted before the earthquake. The Fukushima Daiichi plant is connected to the power grid by four lines, the 500 kV Futaba Line (双葉線), the two 275 kV Ōkuma Lines (大熊線) and the 66 kV Yonomori Line (夜の森線) to the Shin-Fukushima (New Fukushima) substation. The Shin-Fukushima substation also connects to

6195-404: The generators and batteries in that location, but mid-level engineers working on the construction of the plant were concerned that this made the backup power systems vulnerable to flooding. TEPCO elected to strictly follow General Electric's design in the construction of the reactors. The plant is on a bluff which was originally 35 meters above sea level. During construction, however, TEPCO lowered

6300-432: The ground in order to freeze the surrounding groundwater and soil. The wall ultimately failed to significantly decrease the groundwater flowing into the site. The cost of decommissioning and decontamination of the Fukushima Daiichi nuclear power plant has been estimated at $ 195 billion, which includes compensation payouts to victims of the disaster. The amount also includes decommissioning of Fukushima Daiichi reactors, which

6405-403: The height of the bluff by 25 meters. One reason for lowering the bluff was to allow the base of the reactors to be constructed on solid bedrock in order to mitigate the threat posed by earthquakes. Another reason was the lowered height would keep the running costs of the seawater pumps low. TEPCO's analysis of the tsunami risk when planning the site's construction determined that the lower elevation

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6510-406: The highest possible tsunami. Because tsunami walls had been overtopped , the committee also suggested, besides building taller tsunami walls, also teaching citizens how to evacuate if a large-scale tsunami should strike. Large parts of Kuji and the southern section of Ōfunato including the port area were almost entirely destroyed. Also largely destroyed was Rikuzentakata , where the tsunami

6615-449: The incident, as TEPCO had covered it up; interviews of two former workers in 2007 led to its discovery by TEPCO management. A manual shutdown was initiated during the middle of a start-up operation. The cause was a high pressure alarm that was caused by the shutting of a turbine bypass valve. The reactor was at 12% of full power when the alarm occurred at 4:03 am (local time) due to a pressure increase to 1,030 psi (7,100 kPa), exceeding

6720-436: The low-orbiting Gravity Field and Steady-State Ocean Circulation Explorer satellite. Initially, the earthquake caused sinking of part of Honshu's Pacific coast by up to roughly a meter, but after about three years, the coast rose back and then kept on rising to exceed its original height. This megathrust earthquake was a recurrence of the mechanism of the earlier 869 Sanriku earthquake , which has been estimated as having

6825-706: The main shock hit Japan, and continued to occur for 3 hours, during which waves of up to 1.5 meters high were observed. Soil liquefaction was evident in areas of reclaimed land around Tokyo, particularly in Urayasu , Chiba City , Funabashi , Narashino (all in Chiba Prefecture ) and in the Koto , Edogawa , Minato , Chūō , and Ōta Wards of Tokyo. Approximately 30 homes or buildings were destroyed and 1,046 other buildings were damaged to varying degrees. Nearby Haneda Airport , built mostly on reclaimed land,

6930-648: The maximum of 7 on the Japan Meteorological Agency seismic intensity scale in Kurihara , Miyagi Prefecture . Three other prefectures— Fukushima , Ibaraki and Tochigi —recorded a 6 upper on the JMA scale. Seismic stations in Iwate , Gunma , Saitama and Chiba Prefecture measured a 6 lower, recording a 5 upper in Tokyo. Portions of northeastern Japan shifted by as much as 2.4 meters (7 ft 10 in) closer to North America, making some sections of Japan's landmass wider than before. Those areas of Japan closest to

7035-443: The north to Ōarai, Ibaraki , in the south, with most of the destruction in that area occurring in the hour following the earthquake. Near Ōarai, people captured images of a huge whirlpool that had been generated by the tsunami. The tsunami washed away the sole bridge to Miyatojima, Miyagi, isolating the island's 900 residents. A 2 meters (6 ft 7 in) high tsunami hit Chiba Prefecture about 2 + 1 ⁄ 2 hours after

7140-492: The north-western Pacific Ocean at a relatively shallow depth of 32 km (20 mi), with its epicenter approximately 72 km (45 mi) east of the Oshika Peninsula of Tōhoku , Japan, lasting approximately six minutes. The earthquake was initially reported as 7.9 M w by the USGS before it was quickly upgraded to 8.8 M w , then to 8.9 M w , and then finally to 9.0 M w . On 11 July 2016,

7245-555: The ocean – contains the newer units 5 and 6, respectively, the positions from left to right. A set of seawalls protrude into the ocean, with the water intake in the middle and water discharge outlets on either side. Units 7 and 8 were planned to start construction in April 2012 and 2013 and to come into operation in October 2016 and 2017 respectively. The project was formally canceled by TEPCO in April 2011 after local authorities questioned

7350-511: The orbit of the GOCE satellite, which thus serendipitously became the first seismograph in orbit. Following the earthquake, cracks were observed to have formed in the roof of Mount Fuji 's magma chamber . Seiches observed in Sognefjorden , Norway were attributed to distant S waves and Love waves generated by the earthquake. These seiches began to occur roughly half an hour after

7455-504: The plant, and TEPCO announced plans to filter radioactive particles and discharge purified water. In August, Japanese officials said highly radioactive water was leaking from Fukushima Daiichi into the Pacific Ocean at a rate of 300 tons (about 272 metric tons) per day. Japanese Prime Minister Shinzo Abe ordered government officials to step in. By September 2019, one million tons of contaminated cooling water had been collected in tall steel tanks. Large filtration systems were used to clean

7560-645: The plant. Scientists estimate that the accident released 18 quadrillion becquerels of caesium-137 into the Pacific Ocean, contaminating 150 square miles (390 km) of the ocean floor. The events at units 1, 2 and 3 have been rated at Level 5 each on the International Nuclear Event Scale , and those at unit 4 as Level 3 (Serious Incident) events, with the overall plant rating at Level 7 (major release of radioactive material with widespread health and environmental effects requiring implementation of planned and extended countermeasures), making

7665-470: The plant; the releases continue to this day. On April 20, 2011, the Japanese authorities declared the 20 km (12 mi) evacuation zone a no-go area which may only be entered under government supervision. In November 2011, the first journalists were allowed to visit the plant. They described a scene of devastation in which three of the reactor buildings were destroyed; the grounds were covered with mangled trucks, crumpled water tanks and other debris left by

7770-462: The populace warning did not trigger. According to the Japan Meteorological Agency , reasons for the underestimation include a saturated magnitude scale when using maximum amplitude as input, failure to fully take into account the area of the hypocenter , and the initial amplitude of the earthquake being less than that which would be predicted by an empirical relationship. There were also cases where large differences between estimated intensities by

7875-524: The quake, causing heavy damage to cities such as Asahi . On 13 March 2011, the Japan Meteorological Agency (JMA) published details of tsunami observations recorded around the coastline of Japan following the earthquake. These observations included tsunami maximum readings of over 3 meters (9.8 ft) at the following locations and times on 11 March 2011, following the earthquake at 14:46 JST: Many areas were also affected by waves of 1 to 3 meters (3 ft 3 in to 9 ft 10 in) in height, and

7980-532: The rate of aftershocks declines with the reciprocal of the time since the main quake. The aftershocks thus tapered off over time, but continued for years after the initial quake, including one on 26 October 2013 (local time) of magnitude 7.1 M w . The earthquake moved Honshu 2.4 m (8 ft) east, shifted the Earth on its axis by estimates of between 10 and 25 cm (4 and 10 in), increased Earth's rotational speed by 1.8 μs per day, and generated infrasound waves detected in perturbations of

8085-405: The regulatory limit of 1,002 psi (6,910 kPa). The reactor was reduced to 0% power, which exceeded the 5% threshold that requires event reporting, and pressure dropped back under the regulatory limit at 4:25 am. Later, at 8:49 am the control blades were completely inserted, constituting a manual reactor shutdown. An inspection then confirmed that one of the 8 bypass valves had closed and that

8190-458: The risks of the type of boiling water reactors cooling systems such as those in Fukushima I, and claimed the risks were known since 1971 in a series of documentaries in the BBC in 1992 and advised that PWR type reactors should have been used. Tokyo Electric Power Company (TEPCO) operated the station and was warned their seawall was insufficient to withstand a powerful tsunami, but did not increase

8295-400: The seawall height in response. The Onagawa Nuclear Power Plant , operated by Tohoku Electric Power , ran closer to the epicenter of the earthquake, but had much more robust seawalls of greater height and avoided severe accident. Fuel rods fell in reactor No. 3, causing a nuclear reaction. It took about seven and a half hours to place the rods back into proper positions. There was no record of

8400-478: The source area and the seismic moment, it was estimated that the slip deficit of this earthquake was accumulated over a period of 260–880 years, which is consistent with the recurrence interval of such great earthquakes estimated from the tsunami deposit data. The seismic moment of this earthquake accounts for about 93% of the estimated cumulative moment from 1926 to March 2011. Hence, earthquakes in this area with magnitudes of about 7 since 1926 had only released part of

8505-476: The south, is also run by TEPCO. It also suffered serious damage during the tsunami, at the seawater intakes of all four units, but was successfully shut down and brought to a safe state. See the timeline of the Fukushima II nuclear accidents . The March 2011 disaster disabled the reactor cooling systems, leading to releases of radioactivity and triggering a 30 km (19 mi) evacuation zone surrounding

8610-400: The station, which had seawalls, disabled emergency generators required to cool the reactors and spent fuel pools in Units 1–5. Over the following three weeks there was evidence of partial nuclear meltdowns in units 1, 2 and 3: visible explosions, suspected to be caused by hydrogen gas, in units 1 and 3; a suspected explosion in unit 2, that may have damaged the primary containment vessel; and

8715-600: The town by 14 March 2011. Among the factors in the high death toll was the unexpectedly large water surge. The sea walls in several cities had been built to protect against tsunamis of much lower heights. Also, many people caught in the tsunami thought they were on high enough ground to be safe. According to a special committee on disaster prevention designated by the Japanese government, the tsunami protection policy had been intended to deal with only tsunamis that had been scientifically proved to occur repeatedly. The committee advised that future policy should be to protect against

8820-454: The tsunami warning long after the earthquake (28 minutes, according to observations); by that time, power failures and similar circumstances reportedly prevented the update from reaching some residents. Also, observed data from tidal meters that were located off the coast were not fully reflected in the second warning. Furthermore, shortly after the earthquake, some wave meters reported a fluctuation of "20 centimeters (7.9 in)", and this value

8925-469: The tsunami; and radioactive levels were so high that visitors were only allowed to stay for a few hours. In April 2012, Units 1–4 were shut down. Units 2–4 were shut down on April 19, while Unit 1 was the last of these four units to be shut down on April 20 at midnight. In December 2013 TEPCO decided none of the undamaged units will reopen. Units 5 and 6 were shut down later in January 2014. In April 2021,

9030-428: The upper plate down until the accumulated stress causes a seismic slip-rupture event. The break caused the sea floor to rise by several meters. The magnitude of this earthquake was a surprise to some seismologists. A quake of this magnitude usually has a rupture length of at least 500 km (310 mi) and generally requires a long, relatively straight fault surface. Because the plate boundary and subduction zone in

9135-594: The upper refueling hall and eventually exploded causing the refueling hall's blast panels to be forcefully ejected from the structure. Residents within a 20 km (12 mi) radius of the Fukushima Daiichi Nuclear Power Plant and a 10 km (6.2 mi) radius of the Fukushima Daini Nuclear Power Plant were evacuated. Early estimates placed insured losses from the earthquake alone at US$ 14.5 to $ 34.6 billion. The Bank of Japan offered ¥ 15 trillion (US$ 183 billion) to

9240-435: The valve had a bad driving fluid connection. The reactor had been starting up following its 25th regular inspection, which had begun on October 18, 2008. Unit 3 had problems with over-insertion of control blades during outage. Repair work was being done on equipment that regulates the driving pressure for the control blades, and when a valve was opened at 2:23 pm a control blade drift alarm went off. On later inspection, it

9345-420: The warning, 49% were hit by the water. Delayed evacuations in response to the warnings had a number of causes. The tsunami height that had been initially predicted by the tsunami warning system was lower than the actual tsunami height; this error contributed to the delayed escape of some residents. The discrepancy arose as follows: in order to produce a quick prediction of a tsunami's height and thus to provide

9450-460: The water of its radioactive contaminants, but could not remove the estimated 14 grams of tritium , a radioactive isotope of hydrogen (Hydrogen-3) bonded into water molecules. TEPCO estimated the immediate site would run out of space by 2022, and planned to solve this problem by releasing the radioactive water into the Pacific Ocean . This proposed measure was criticised by environmental groups and several Asian governments, who claimed that storage area

9555-484: Was also particularly hard hit. At least 101 designated tsunami evacuation sites were hit by the wave. Like the 2004 Indian Ocean earthquake and tsunami , the damage by surging water, though much more localized, was far more deadly and destructive than the actual quake. Entire towns were destroyed in tsunami-hit areas in Japan, including 9,500 missing in Minamisanriku ; one thousand bodies had been recovered in

9660-529: Was available in the exclusion zone around the reactor. Japan's government approved the release, beginning in 2023, over the course of an estimated 40 years. A note in the 2020 Tokyo Olympic Games opening speech referenced the disaster and how Japan has recovered from the disaster. The reactors will take 30–40 years to be decommissioned. On August 1, 2013, the Japanese Industry Minister Toshimitsu Motegi approved

9765-413: Was broadcast throughout the mass media and the warning system, which caused some residents to underestimate the danger of their situation and even delayed or suspended their evacuation. In response to the aforementioned shortcomings in the tsunami warning system, JMA began an investigation in 2011 and updated their system in 2013. In the updated system, for a powerful earthquake that is capable of causing

9870-433: Was cut off across much of northern Japan including the loss of external power to Higashidōri Nuclear Power Plant and Rokkasho Reprocessing Plant . Four days later on 11 April, another magnitude 7.1 M w aftershock struck Fukushima, causing additional damage and killing a total of three people. On 7 December 2012 a large aftershock of magnitude 7.3 M w caused a minor tsunami, and again on 26 October 2013

9975-432: Was designed for a peak ground acceleration of 0.18  g (1.74 m/s) and a response spectrum based on the 1952 Kern County earthquake , but rated for 0.498 g. The design basis for Units 3 and 6 were 0.45 g (4.41 m/s) and 0.46 g (4.48 m/s) respectively. All units were inspected after the 1978 Miyagi earthquake when the ground acceleration was 0.125 g (1.22 m/s) for 30 seconds, but no damage to

10080-440: Was done by Ebasco . All construction was done by Kajima . Since September 2010, Unit 3 has been fueled by a small fraction (6%) of plutonium containing mixed-oxide (MOX) fuel , rather than the low enriched uranium (LEU) used in the other reactors. Units 1–5 were built with Mark I type (light bulb torus) containment structures . The Mark I containment structure was slightly increased in volume by Japanese engineers. Unit 6 has

10185-446: Was focused on organizing a set of important and urgent documents in the main office building of the Fukushima Daiichi Nuclear Power Plant as a member of the accounting team. In April 2013, TEPCO publicly admitted radionuclide contaminated water may have leaked from the storage units, possibly contaminating the soil and water nearby. The leak was controlled and stored in containment tanks. Contaminated water continued to accumulate at

10290-406: Was found that several of the rods had been unintentionally inserted. Unit 5 had an automatic SCRAM while an operator was conducting an adjustment to the control blade insertion pattern. The SCRAM was caused by a reactor low water level alarm. The turbine tripped along with the reactor and there was no radiation injury to workers. On March 11, 2011, an earthquake categorized as 9.1 M W on

10395-619: Was not damaged. Odaiba also experienced liquefaction, but damage was minimal. Shinmoedake , a volcano in Kyushu , erupted three days after the earthquake. The volcano had previously erupted in January 2011; it is not known if the later eruption was linked to the earthquake. In Antarctica , the seismic waves from the earthquake were reported to have caused the Whillans Ice Stream to slip by about 0.5 meters (1 ft 8 in). The first sign international researchers had that

10500-441: Was safe because the sea wall would provide adequate protection for the maximum tsunami assumed by the design basis. However, the lower site elevation did increase the vulnerability for a tsunami larger than anticipated in design. The Fukushima Daiichi site is divided into two reactor groups, the leftmost group – when viewing from the ocean – contains units 4, 3, 2 and 1 going from left to right. The rightmost group – when viewing from

10605-554: Was scattered on the high cliff above the bay. At Tarō, Iwate , the tsunami reached a height of 37.9 meters (124 ft) up the slope of a mountain some 200 meters (660 ft) away from the coastline . Also, at the slope of a nearby mountain from 400 meters (1,300 ft) away at Aneyoshi fishery port ( 姉吉漁港 ) of Omoe peninsula ( 重茂半島 ) in Miyako, Iwate , Tokyo University of Marine Science and Technology found estimated tsunami run up height of 38.9 meters (128 ft). This height

10710-471: Was struck by waves 2 meters (6.6 ft) high, compared with an estimated wave height of 38.9 meters (128 ft) at Omoe peninsula, Miyako city, Japan. The tsunami warning issued by the Japan Meteorological Agency was the most serious on its warning scale; it was rated as a "major tsunami", being at least 3 meters (9.8 ft) high. The actual height prediction varied, the greatest being for Miyagi at 6 meters (20 ft) high. The tsunami inundated

10815-435: Was subsequently modified to handle this kind of situation. An upthrust of 6 to 8 meters (20 to 26 ft) along a 180-kilometer (110 mi)-wide seabed at 60 kilometers (37 mi) offshore from the east coast of Tōhoku resulted in a major tsunami that brought destruction along the Pacific coastline of Japan's northern islands. Thousands of people died and entire towns were devastated. The tsunami propagated throughout

10920-572: 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 40.5 meters (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

11025-687: Was three stories high. Other cities destroyed or heavily damaged by the tsunami include Kamaishi , Miyako , Ōtsuchi , and Yamada (in Iwate Prefecture), Namie , Sōma , and Minamisōma (in Fukushima Prefecture) and Shichigahama , Higashimatsushima , Onagawa , Natori , Ishinomaki , and Kesennuma (in Miyagi Prefecture). The most severe effects of the tsunami were felt along a 670-kilometer-long (420 mi) stretch of coastline from Erimo, Hokkaido , in

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