Great East Japan Earthquake and Tsunami, Accident (1/5) < About Great East Japan Earthquake and Tsunami > Date and Time: March 11, 2011 14:46 JST Epicenter: Off the Sanriku coast (38 6.2 N, 142 52 E) Depth 24Km Magnitude: 9.0 Distribution of JMA* Seismic Intensity Source: JMA website The JMA seismic intensities observed in Prefecture are as follows: JMA Seismic Intensity Location 6 Upper Shirakawa, Sukagawa, Kunimi, Tenei, Tomioka, Okuma, Namie, Kagamiishi, Naraha, Futaba and Shinchi 6 Lower, Nihonmatsu, Motomiya, Koriyama, Koori, Kawamata, Nishigo, Yabuki, Nakajima, Tamakawa, Ono, Tanagura, Date, Hirono, Asakawa, Tamura, Iwaki, Kawauchi, Iitate, Soma, Minamisoma and Inawashiro 5 Upper Otama, Izumizaki, Yamatsuri, Hirata, Ishikawa, Miharu, Katsurao, Furudono, Aizuwakamatsu, Aizubange, Kitakata, Yugawa, Aizumisato and Bandai (Translation of Prefecture report) 2. Overview of the Tsunami The tsunami which followed the earthquake caused much more damage. In a wide area from Hokkaido to Okinawa, particularly along the Pacific coast mainly from Tohoku to North Kanto, the tsunami was observed. In, the maximum height of the tsunami observed was higher than 9.3m. The tsunami inundated as wide as 112km 2 and caused enormous damage. The tsunami data observed at the observation stations in Prefecture are as follows: * Japan Meteorological Agency 1. Overview of the earthquake On March 11, 2011, the earthquake occurred centered off the Sanriku coast. The magnitude was 9.0, far beyond the scale of the Kanto Great Earthquake (M7.9) in 1923 and Showa Sanriku Earthquake (M8.4) in 1933, the biggest earthquake ever in and around Japan. Soon after the earthquake, the JMA named it as 2011 off the Pacific coast of Tohoku Earthquake. On April 1, 2011, the cabinet decided to call the disaster caused by the earthquake and the following Daiichi Nuclear Power Plant accident Great East Japan Earthquake. First Wave Maximum Height Area Date Time Type Height Date Time Height Soma March 11, 2011 14:-- Backwash 1.2m March 11, 2011 15:51 >=9.3m *1 *2 *3 *4 Onahama, Iwaki *3 March 11, 2011 15:08 Anaseism 2.6m March 11, 2011 15:39 3.3m (Translation of JMA report, March 2011) Note: Since the observation stations were damaged by the tsunami, data could not be retrieved for some time and the subsequent waves may have been higher than the data listed. *1 Data could not be retrieved for some time. *2 Observed by a massive tsunami observation instrument (per 0.1m). *3 Readings of the first wave may have been inaccurate due to the land subsidence effect. *4 The beginning time of the first wave could not be identified by the sea-level fluctuations caused by the earthquake. However, the occurrence of land subsidence along the Pacific coast after the earthquake is estimated by Geospatial Information Authority of Japan. Therefore, it is estimated that the coast was included in the source area of tsunami. The 2011 Great East Japan Earthquake (JMA): http://www.jma.go.jp/jma/en/2011_earthquake/information_on_2011_earthquake.html
Great East Japan Earthquake and Tsunami, Accident (2/5) < About TEPCO s Daiichi Nuclear Power Plant Accident > Situation soon after the accident occurrence The massive earthquake automatically shut down the Units 1, 2 and 3 which were being operated at TEPCO s Daiichi Nuclear Power Plant ( ). At that time, Units 4, 5 and 6 were not operated because they were being checked or tested. Since the earthquake lost all external power sources at the, the emergency diesel generators automatically started running and maintained the cooling function of the reactors and spent fuel pools. However, the subsequent tsunami discontinued the operation of the emergency generators resulting in all AC power sources lost for Units 1 to 4. TEPCO took measures to recover power source in cooperation with the government, but they faced difficulties. The isolation condenser of Unit 1 became inoperable. At Units 2 and 3, DC power source ran out and the supply of cooling water stopped. These led to dysfunction of core cooling system at each Unit. As a result, the water level of the reactors lowered and the reactor cores were exposed. The reactors began to be damaged and were finally melt down. After that, there were hydrogen explosions at Unit 1 and 3 around the roof top of the reactor building. The explosions are estimated to have been caused by hydrogen leaked from the containment. The explosions destroyed the operation floor of each building. These explosions released a huge amount of radioactive materials into the atmosphere. Following the explosion at the Unit 3 building, there was another explosion at Unit 4 where all reactor fuel had been moved to its spent fuel pool due to a regular check. The explosion is estimated to have been caused by hydrogen. The upper part of the reactor building was destroyed. During this period of time, a large damage is estimated to have occurred at Unit 2 probably around its suppression chamber room. The Japanese government issued Declaration of Daiichi Emergency Situation, followed by evacuation order to residents within the 3km radius of. Next day (March 12), at 5:44, the government expanded the evacuation from 3km to 10km after the radiation level in the center control room of Unit 1 rose. Following the hydrogen explosion at Unit 1 at 15:36 on that day, the evacuation was further expanded to 20km at 18:25. At 11:01 on March 14, another hydrogen explosion was confirmed at Unit 3. At 6;10 on March 15, an explosion was heard at Unit 4 and then the government ordered sheltering indoors to 140,000 residents within the 20-30km radius area of the power plant at 11:00. Extended evacuation s (as of Mar. 11, 2011) (as of Mar. 12, 2011) (as of Mar. 15, 2011)
Great East Japan Earthquake and Tsunami, Accident (3/5) < Accident: Timeline from the accident occurrence (2011) > 2011/03/11 14:46 "2011 off the Pacific Coast of Tohoku Earthquake" occurred. Magnitude: 9.0; Seismic intensity observed: 6 lower ( City); Maximum intensity observed: 7 (North Miyagi Prefecture). The following reactors were automatically shut down: Units No. 1 to 3 at and Units No. 1 to 4 at Daini NPP. Units 4 to 6 at were in a regular check. The disaster response headquarters were established by Prefecture and the disaster security headquarters by Prefectural Police. (49 municipalities in Prefectures also established their own disaster response headquarters.) 14:49 The Japan Meteorological Agency issued a major tsunami warning to the Pacific coastal regions of the following prefectures: Aomori; Iwate; Miyagi; and. 14:50 The Japanese Government established the Response Office at the Prime Minister's Office. => The government established the Disaster Management Headquarters at 15:14. 15:37 lost its power source due to the tsunami. => 15:42 TEPCO notified the government of the event based on Act on Special Measures concerning Nuclear Emergency Preparedness 19:03 The government issued "Declaration of Emergency Situation". 20:50 The Prefecture Nuclear Disaster Headquarters "requested evacuation" to residents within a radius of 2 km from Unit 1 of. 21:23 The government ordered evacuation to 5,862 residents within 3 km radius of, and ordered sheltering indoors to residents of the radius of 3-10 km from the NPP. 2011/03/12 5:44 The government ordered evacuation to 51,207 residents within 10km radius of. 7:45 The government issued "Declaration of Daini NPP Emergency Situation". 7:45 The government ordered evacuation to 8,049 residents within 3km radius of Daini NPP and sheltering indoors to residents within 3-10km radius of the power plant. 15:36 Hydrogen explosion at Unit 1 of. 17:39 The government ordered evacuation to 32,426 residents within 10km radius of Daini NPP. 18:25 The government ordered evacuation to about 80,000 residents within 20km radius of. 19:04 Seawater injection into the reactor of started. Translation of the following references and websites: Reports (The National Diet of Japan Nuclear Accident Independent Investigation Commission); Reports (Investigation Committee on the Accident at the Nuclear Power Stations of Tokyo Electric Power Company established by the cabinet decision); Prime Minister s Office website; Cabinet Office s website; Ministry of Economy, Trade and Industry s website; Japan Meteorological Agency s website; and excerpts from Great East Japan Earthquake and Tsunami Record Document of published by JRCS Chapter. 2011/03/14 2011/03/15 2011/03/16 11:01 Hydrogen explosion in the Unit 3 building of Daiichi NPP. 18:22 All fuel rods at Unit 2 of were exposed due to shortage of cooling water. around 6:00 An impulsive sound presumably from damage around the pressure suppression room in Unit 2 of was confirmed. A significant impulsive sound was heard from Unit 4 of the NPP. The roof top area on the fifth floor of the reactor building was damaged. 11:00 Residents within 20-30km radius of were ordered to stay indoors. 5:45 Fire occurrence around the north-west part of the third floor of Unit 4 reactor building of was confirmed. 8:34 A large grey smoke rising from Unit 3 was observed. 2011/03/17 Water spraying into the Unit 3 spent fuel pool was conducted by police and Self-Defense Forces. 2011/03/18 Water spraying into the Unit 3 spent fuel pool was carried out by Self-Defense Forces and the U.S. Army using high-pressure water cannon vehicles. Nuclear and Industrial Safety Agency issued Level 5 (Accident with off-site risk) INES provisional rating for Units 1 to 3. 2011/03/19 Emergency Fire Rescue Team of Fire and Disaster Management Agency sprayed water to the Unit 3 spent fuel pool. 2011/03/20 Unit 5 at was in cold shutdown. Unit 6 at was in cold shutdown. 2011/03/23 Estimates for radioactive effects using SPEEDI was announced. 2011/03/25 The government requested mayors of municipalities in the areas where sheltering order was issued (20-30 km radius of ) for active encouragement of voluntary evacuation to their citizens and for beginning preparations on the assumption evacuation order issuance. 2011/04/01 The government named the disaster as "Great East Japan Earthquake". 2011/04/04 Low-level radioactive contaminated water was discharged into the ocean. 2011/04/12 The INES provisional rating was raised to Level 7 (Major accident) for Units 1-3. 2011/04/17 TEPCO released "Roadmap towards Restoration from the Accident at Daiichi Nuclear Power Station". Reports (The National Diet of Japan Nuclear Accident Independent Investigation Commission) http://warp.da.ndl.go.jp/info:ndljp/pid/3856371/naiic.go.jp/ en/ Reports (Investigation Committee on the Accident at the Nuclear Power Stations of Tokyo Electric Power Company established by the cabinet decision) http://www.cas.go.jp/jp/seisaku/icanps/eng/
Great East Japan Earthquake and Tsunami, Accident (4/5) < Spread of radioactive materials from > The accident released radioactive materials such as Cs-134 and Cs-137 whose half-life period is long over a wide area. Due to this, there are still many areas with high ambient dose rate as of February 2013, about two years on from the accident. Akita Iwate Yamagata Miyagi Niigata TEPCO TEPCO Tochigi Gunma Ibaraki Saitama Results of aircraft monitoring by MEXT* and Miyagi Prefecture (Total surface deposition of Cs 134 and Cs 137 inside 100 and 120 km zone of TEPCO and in northern Miyagi Prefecture) (as of July 2, 2011) * Ministry of Education, Culture, Sports, Science and Technology Yamanashi Tokyo Source: Excerpts from aircraft monitoring readings released by MEXT Chiba Air dose rate map (Air dose rate over 1 meter above ground level) (Combination of the 6 th aircraft monitoring results and readings of air dose monitoring outside 80km zone of TEPCO Daiichi NPP) (as of February 28, 2013)
Great East Japan Earthquake and Tsunami, Accident (5/5) < Wide-area evacuation caused by the accident > The unprecedented complicated disaster of the huge earthquake and tsunami which occurred on March 11, 2011 and the subsequent nuclear accident extended evacuation s. Finally, evacuation order was issued over a wide area and this forced a large number of residents to flee their homes. Many citizens including families with children evacuated to other prefectures, because they were concerned about radiation effects. Extended evacuation s (Some descriptions are added to the evacuation area maps posted on the METI*website) Deliberate Area Prepared Area in Case of Emergency Sheltering indoors Sheltering indoors Daini NPP Prepared Area in Case of Emergency Daini NPP March 11, 2011 (3km radius of the NPP) April 21, 2011 (Extended to 20km radius) April 22, 2011 (Redefined evacuation areas made residents outside a 30km radius of the NPP evacuate.) Number of evacuees by year Pref. Miyagi Pref. Iwate Pref. As of March 2015, there were 71,399 evacuees inside Pref. 46,902 citizens were evacuated outside of the prefecture. The number of the evacuees to other prefectures was much higher than that for other affected prefectures. Note: The charts were prepared based on the data of the Reconstruction Agency website.