Sanriku ( 三陸 ) , sometimes known as Rikushū ( 陸州 ) , lies on the northeastern side of the island of Honshu , corresponding to today's Aomori , Iwate and parts of Miyagi Prefecture and has a long history.
89-550: The 36 bays of this irregular coastline tend to amplify the destructiveness of tsunami waves which reach the shores of Sanriku, as demonstrated in the damage caused by the 2011 Tōhoku earthquake and tsunami . On January 19, 1869, in the aftermath of the Boshin War , the provinces of Mutsu and Dewa were divided. Mutsu was split into new five provinces: Rikuō (also read Mutsu ), Rikuchū , Rikuzen , Iwashiro and Iwaki . The first three of these collectively known as
178-815: 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 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
267-519: 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
356-455: 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
445-520: 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
534-428: A maximum intensity of VII (Very strong) . 14 people were injured and more than 1,900 homes briefly lost electricity. Though a warning of a possible tsunami of 3 m (9.8 ft) in height was issued, a 60 cm (24 in) wave was reported by NHK in the port of Onahama of Iwaki, Fukushima ; a 90 cm (35 in) wave hit Sōma, Fukushima ; and another wave 1 m (3 ft 3 in) in height struck
623-535: 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
712-478: 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
801-467: 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
890-399: 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
979-401: 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
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#17327729488471068-496: 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
1157-509: Is a nuclear power plant located on a 150 ha (370-acre) site in the town of Naraha and Tomioka in the Futaba District of Fukushima Prefecture , Japan. The Tokyo Electric Power Company (TEPCO) runs the plant. After the 2011 Tōhoku earthquake and tsunami , the four reactors at Fukushima Daini automatically shut down . While the sister plant Fukushima Daiichi Nuclear Power Plant , approximately 12 km (7.5 mi) to
1246-542: 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
1335-474: 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
1424-565: The Fukushima Daiichi Nuclear Power Plant site after the 6.9 shock. Chief Cabinet Secretary Yoshihide Suga said that the third reactor's spent fuel pool cooling systems at Fukushima Daini had stopped as a result of the earthquake; TEPCO later reported the restart of the spent fuel cooling system after only 100 minutes of stoppage. On 31 July 2019, the TEPCO board of directors decided to decommission
1513-675: The Oshika Peninsula in Miyagi. This Japanese location article is a stub . You can help Misplaced Pages by expanding it . 2011 T%C5%8Dhoku earthquake and tsunami On 11 March 2011, at 14:46 JST (05:46 UTC ), 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
1602-518: 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, the USGS further upgraded the earthquake to 9.1. Sendai was the nearest major city to the earthquake, 130 km (81 mi) from
1691-471: 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 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
1780-500: 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 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
1869-462: The "Three Riku", or Sanriku , with san (三) meaning "three." The new provinces became quickly obsolete in July 1871 when the abolition of the han system divided Japan into its present prefectures that became the sole divisions used by the government. However, the label lives on in common usages such as the Sanriku Coast , which extends along Japan's Pacific coastline from Aomori in the north down to
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#17327729488471958-544: 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
2047-493: 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
2136-399: 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
2225-427: 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
2314-523: 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
2403-706: 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
2492-457: 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,
2581-542: The RCIC shuts down automatically. The normal electrically driven Emergency Core Cooling Systems (ECCS) were for the most part unavailable due to the loss of the ultimate heat sink and damage to some of the electrical infrastructure. Operators prepared for this and set up an alternate injection line using a non-emergency system known as the Makeup Water Condensate (MUWC) system to maintain water level which
2670-547: 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
2759-401: 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
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2848-520: 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
2937-468: 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
3026-424: 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
3115-518: 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
3204-461: 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
3293-531: 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
3382-428: 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
3471-476: 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
3560-505: 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
3649-497: 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
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3738-401: 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
3827-441: 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
3916-411: The earthquake, and the diesel engines were started to power the reactor cooling. A worker died of injuries from the earthquake when he was trapped in the crane operating console of the exhaust stack. The tsunami that followed the earthquake and inundated the plant was initially estimated by TEPCO to be 14 meters high, which would have been more than twice the designed height. Other sources give
4005-431: 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,
4094-434: 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 the epicenter of the 11 March earthquake, with another three on the same day in excess of 6.0 M w . Following
4183-422: The evacuation order for Naraha was completely lifted, allowing residents to return and reconstruction efforts to begin. Naraha is the first of a number of towns in the area to have had its evacuation order removed. On Tuesday, November 22, 2016, a magnitude 6.9 earthquake struck Japan 37 km (23 mi) east southeast of Namie , Fukushima Prefecture at a depth of 11.3 km (7.0 mi). The shock had
4272-406: 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
4361-436: 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
4450-408: 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 the rate of aftershocks declines with the reciprocal of
4539-706: 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,
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#17327729488474628-648: 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
4717-443: 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
4806-659: The north, suffered extensive damage, the Daini Plant was back under control within two days, reaching cold shutdown. The plant has not been operating since, and in July 2019 a decision to decommission the plant was made. All reactors in the Fukushima II Nuclear Power Plant are BWR-5 type with electric power of 1,100 MW each (net output: 1,067 MW each). The reactors for units 1 and 3 were supplied by Toshiba , and for units 2 and 4 by Hitachi . Units 1–3 were built by Kajima while
4895-402: The operators prepared to vent the containments making restoration of heat removal urgent. Unit 1 was prioritized as it had the highest drywell pressure. The ultimate heat sink was restored on March 13 when the service seawater system pumps in the pump room were repaired in units 1, 2 and 4. This allowed the restoration of the normal ECCS and heat removal systems to operable status and cooling
4984-511: 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
5073-438: The plant worked to stabilize the reactors. Some employees connected over 9 kilometers of cabling using 200-meter sections of cable, each weighing more than a ton, from their Rad Waste Building to other locations onsite. The steam-powered reactor core isolation cooling system (RCIC) in all 4 units was activated and ran as needed to maintain water level. At the same time, operators utilized the safety relief valve systems to keep
5162-406: The pools of units 1, 2, and 4 reached 100 °C between 05:30 and 06:10 JST , removing the ability to remove pressure from the reactor and drywell. Operators had to also prepare an alternate injection line for each unit, as the RCIC can run indefinitely only while there is sufficient pressure and steam in the reactor to drive its turbine. Once the reactor pressure drops below a certain level,
5251-462: 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
5340-524: 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
5429-421: The reactor pressures from getting too high by dumping the heat to the suppression pools. In unit 3, one seawater pump remained operational and the residual heat removal system (RHR) was started to cool the suppression pool and later brought the reactor to cold shutdown on March 12. In units 1, 2, and 4 heat removal was unavailable, so the suppression pools began heating up and on March 12, the water temperature in
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#17327729488475518-666: The reactor to prevent the drywell pressure from getting too high. Operators were later able to restore the High Pressure Core Spray portion of the ECCS in unit 4 and switched emergency water injection for unit 4 from the MUWC system to the HPCS. While the water level was maintained in the three cores using emergency water injection, pressures in the containment vessel continued to rise due to lack of suppression pool cooling and
5607-421: The reactors to a cold shutdown. Coolant temperatures below 100 °C ( cold shutdown ) were reached in reactor 2 about 34 hours after the emergency shut down ( scram ). Reactors 1 and 3 followed at 1:24 and 3:52 on March 14 and Reactor 4 at 7:00 on March 15. By March 15, all four reactors of Fukushima II reached cold shutdown, which remained non-threatening. The loss of cooling water at reactors 1, 2 and 4
5696-444: The situation is under observation. About 90 seconds after an earthquake, an additional report on the possibility of a tsunami will also be included in observation reports, in order to warn people before the JMA magnitude can be calculated. Fukushima Daini Nuclear Power Plant The Fukushima Daini Nuclear Power Plant ( 福島第二原子力発電所 , Fukushima Daini ( pronunciation ) Genshiryoku Hatsudensho , Fukushima II NPP, 2F)
5785-478: 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
5874-722: 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 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
5963-476: 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
6052-600: 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
6141-535: The tsunami height at Fukushima Daini plant at 9-meter-high, while the Fukushima Daiichi plant was hit by a 13-meter-high tsunami. The tsunami caused the plant's seawater pumps, used to cool reactors, to fail. Of the plant's four reactors, three were in danger of meltdown. One external high-voltage power line still functioned, allowing plant staff in the central control room to monitor data on internal reactor temperatures and water levels. 2,000 employees of
6230-564: 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 the Fukushima Daiichi nuclear disaster , primarily the meltdowns of three of its reactors, the discharge of radioactive water in Fukushima and
6319-454: 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
6408-578: The unit 4 was built by Shimizu and Takenaka . The Fukushima Daini plant is connected to the rest of the power grid by the Tomioka Line ( 富岡線 ) to the Shin-Fukushima (New Fukushima) substation. In January 1989, an impeller blade on one of the reactor coolant pumps in Unit 3 broke at a weld, causing a large amount of metal debris to flow throughout the primary loop. As a result, the reactor
6497-428: 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
6586-420: 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
6675-531: The water were beginning to corrode. Approximately 3,000 tons of the water was found to contain radioactive substances, and Japan's Fisheries Agency refused permission to release that water back into the ocean. On December 26, 2011, the Prime Minister officially cancelled the nuclear emergency declaration for the Fukushima Daini plant officially ending the incident. On February 8, 2012, the plant
6764-484: 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
6853-412: Was an accident mitigation method TEPCO put in place at all its nuclear plants. The system was started and stopped in all 4 units, including unit 3, as needed to maintain the water level. The RCICs in each unit later shut down due to low reactor pressure. The MUWC and the makeup water purification and filtering (MUPF) systems were also used to try to cool the suppression pool and drywell in addition to
6942-413: 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
7031-510: Was classified a level 3 on the International Nuclear Event Scale (serious incident) by Japanese authorities as of March 18. Officials made preparations for release of pressure from the plant on March 12, but no pressure release was necessary. An evacuation order was issued to the people living within 3 kilometres (1.9 mi) of the plant, subsequently expanded to 10 km (6.2 mi). Air traffic
7120-433: 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
7209-674: 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
7298-475: Was opened to news media for the first time since the 2011 Tōhoku earthquake and tsunami. The evacuation order was partly rescinded for Daini evacuees in August 2012. Some of the residents, such as the 7200 at Naraha , were permitted to return during daylight hours only, but others were ordered to remain away. The area did not become seriously contaminated and was safe to visit without protective clothing. In 2015,
7387-423: Was restricted in a 10 km (6.2 mi) radius around the plant, according to a NOTAM . These zones were later superseded by the 20 km evacuation and 30 km no-fly zones around Fukushima Daiichi on March 12 and 15, respectively. As of June 2011 , 7,000 tons of seawater from the tsunami remained in the plant. The plant planned to release it all back into the ocean, as the tanks and structures holding
7476-502: 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
7565-468: Was shut down for a considerable length of time. The March 11, 2011 Tōhoku earthquake resulted in maximum horizontal ground accelerations of 0.21 g (2.10 m/s ) to 0.28 (2.77 m/s ) at the plant site, which is well below the design basis. The design basis accident for an earthquake was between 0.42 g (4.15 m/s ) and 0.52 g (5.12 m/s ) and for a tsunami was 5.2 m. All four units were automatically shut down ( scram ) immediately after
7654-471: 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
7743-435: 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
7832-646: Was switched to the Residual Heat Removal System (RHR) portion of the ECCS. The RHR systems were first activated to cool down the suppression pools (torus) and drywells to operable status, and water injections were made to the reactors using the Low Pressure Coolant Injection (LPCI) mode as needed. When the suppression pool was cooled down to below 100 °C, the RHR was switched to the shutdown cooling mode and brought
7921-687: 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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