what happened at fukushima daiichi nuclear plant?
2011 Tōhoku earthquake and tsunami
contradiction
 The Fukushima Hamadōri earthquake was succeeded by a number of smaller tremors ; that same day , at least 11 earthquakes of magnitude 3 @.@ 5 Mj or higher were recorded near its epicentre . Of the series , the strongest registered at a magnitude of 5 @.@ 5 Mj and occurred within 3 @.@ 5 hours after the initial quake . A shallow magnitude 6 @.@ 0 Mw ( 6 @.@ 4 Mj ) earthquake and several smaller tremors struck the region on 12 April . 

entailment
 The earthquake struck in the late afternoon near a moderately populated region of the Fukushima Prefecture , although most structures around the epicentre were resistant to earthquake shaking . Focussed at an unusually shallow depth , the earthquake generated significant shaking throughout many adjacent prefectures . The strongest ground motion registered at severe ( MM VIII ) in Ishikawa town on the Mercalli intensity scale . Strong shaking ( MM VI ) spread through Iwaki , Sukawaga , Kuroiso , Ōtawara and Kitaibaraki , with light tremors ( MM IV ) felt in areas up to several hundred kilometres from the epicentre , including Tokyo and Yokohama . The earthquake cut electricity to about 220 @,@ 000 households , with most of the cuts reported in Iwaki city . Workers at the Fukushima Daiichi power plant – distanced 70 km ( 43 mi ) from the epicentre – evacuated to safety , and external power to the plant was cut . The outage briefly disrupted cooling water injections into three of the reactors , but services to the plant were restored by 18 : 05 JST . Authorities at Tokyo International Airport closed all runways momentarily , while NTT DoCoMo restricted voice calls in 14 prefectures following the quake . East Japan Railway Company temporarily suspended its services to restart four of five bullet @-@ train lines ; other Shinkansen bullet trains in the region were also halted . 

contradiction
 The Fukushima Hamadōri earthquake occurred in a region with historically low levels of seismicity ; studies showed that the recent activity near the fault zone had been triggered by the Tōhoku earthquake . Ever since the earthquake triggered their reactivation , the Shionohira and Yunodake faults have provided essential data for local geological surveys on regional land deformation , sedimentary rock distribution and landslide vulnerability . In the earthquake 's aftermath , Professor Yagi Hiroshi from the Faculty of Education , Art and Science noted that " a possibility exists for widespread aftershocks of the same size to occur in the near future . " 

neutral
 Two major events precede the story , known as the Bloody Valentine tragedy that initiated war between the PLANTS and the Earth Forces when one of the PLANT space stations , Junius @-@ 7 , is destroyed by a nuclear bomb . The second event is the counterattack by the PLANTS that buries Neutron Jammers deep into Earth 's crust that halts all nuclear reactions and long range radar and radio , causing most areas of earth to go without electricity or communication , and requiring mobile suits to rely on rechargeable batteries . 

neutral
 The Chinese authorities immediately launched a full investigation into the disaster , which concluded a week later on April 23 . The factory itself was sealed off for the course of the investigation , a common practice in China , but work continued in the site office . 
