The2011 Tōhoku earthquake and tsunami was a 9.0-magnitudeearthquake followed bytsunami waves.[8] It was measured at 8.4 on theJMAseismic intensity scale[9][10] The earthquake happened 130 kilometres (81 mi) offSendai,Miyagi Prefecture, on the east coast of theTōhoku ofJapan, on March 11, 2011 at 05:46:23 UTC. It was at a depth of 24.4 km (15.2 miles).[11] It was the most powerful earthquake to hit Japan in recorded history.[12] It was also the fourth most powerful earthquake onEarth since record-keeping began in 1900.
Days before the main earthquake, there were severalforeshocks. The biggest one was a 7.2 magnitude earthquake on 9 March, about 40 kilometres (25 mi) from the main earthquake's location.
The United States Geological Survey said the centre of the earthquake was 373 kilometres (232 mi) fromTokyo. A 7.7aftershock happened 30 minutes following the first quake. There have been more than 600aftershocks bigger than magnitude 4.5 or more.[14]
The earthquake started fires. TheShinkansen high speed bullet trains were stopped andHaneda Airport was closed after the quake.[15] Various train services around Japan were also stopped. Hundreds of flights to Japan were cancelled due to the earthquake and tsunami, affecting many people.[16] A large fire broke out at anoil refinery in Ichihara, Chiba prefecture.
At 9:28 p.m (HST) theNational Weather Service issued a tsunami warning until 7 a.m. for all ofHawaii.[24] Tsunami waves were expected to arrive in Hawaii at 2:59 am local time.[25] A wave two meters high reachedCalifornia, after travelling across thePacific Ocean at a speed of 500 kilometres per hour.[23] A man in California was drowned after being swept into the ocean while trying to take a photograph of the tsunami wave.[26]
The JapaneseNational Police Agency has officially confirmed 15,890 deaths, 6,152 injured, and 2,590 people missing across 18prefectures, as well as over 126,000 buildings damaged or destroyed.[13]
TheFukushima nuclear disaster began on March 11 2011, just hours after the initial wave.[27][28] The connection to the electrical grid was broken. All power for cooling was lost and reactors started to overheat. There was a partialcore meltdown in reactors 1, 2, and 3;hydrogen explosions destroyed the upper part of the buildings housing reactors 1, 3, and 4; an explosion damaged the containment inside reactor 2; fires broke out at reactor 4. Despite being initially shutdown, reactors 5 and 6 began to overheat. Spent nuclear fuel rods stored in pools in each reactor building overheated as water levels in the pools dropped. The accident is the second biggestnuclear accident after theChernobyl disaster, but more complex as all reactors are involved.[29]
There were 4.4 million households that had their electricity supply cut off, including 11 nuclear power plants.[30]
The quake moved parts of northeast Japan as much as 2.4 meters (7.9 ft) closer to North America,[31][32] making parts of Japan's land "wider than before," according togeophysicist Ross Stein.[32] Areas of Japan closest to the epi-center shifted the most.[32]
The Pacific plate itself may have moved westwards by up to 20 m (66 ft).[33] Other estimates put the amount of slippage at as much as 40 m (130 ft), covering an area some 300 to 400 km (190 to 250 mi) long by 100 km (62 mi) wide. If confirmed, this would be one of the largest recorded fault movements to have been associated with an earthquake.[34]
According to Italy's National Institute of Geophysics and Volcanology, the earthquake shifted the Earth'saxis by 25 centimeters (9.8 in). This deviation led to a number of small planetary changes, including the length of a day and thetilt of the Earth.[35] The speed of the Earth's rotation increased, shortening the day by 1.8 microseconds due to the redistribution of Earth'smass.[36]
The axial shift was caused by the redistribution of mass on the Earth's surface, which changed the planet'smoment of inertia. Due to the conservation ofangular momentum, such changes ofinertia result in small changes to the Earth's rate of rotation.[37] These are expected changes for an earthquake of this magnitude.[31][35][36]
The Tōhoku Expressway, which serves northern Japan, had to be closed due to cracks on the roads.[38] The whole railway network was closed, but was reopened hours after the earthquake. Up to 100,000 people were stuck waiting for a ride straight out of the city.[39]
In response to the great disaster,Emperor Akihito directly addressed his subjects in a television broadcast. This was the first time any emperor had used television in this way.[40]
There were other people from other countries helping people after this disaster. For example,Google set up a people finder service, which allowed users to ask for or post information about missing people.[41][42]
↑Japan Meteorological Agency (ed.)."「平成23年（2011年）東北地方太平洋沖地震」について～７年間の地震活動～" ["About 2011 Tōhoku earthquake - Seismic activities for 7 years -"](PDF). Retrieved2018-06-18. on 6 March 2018.
↑"Tsunami Warnings/Advisories".Japan Meteorological Agency. Japan Meteorological Agency.Archived from the original on 2011-03-12. Retrieved11 March 2011.
↑"Analysis: A month on, Japan nuclear crisis still scarring,"International Business Times (Australia). 9 April 2011, retrieved 12 April 2011; excerpt, According toJames Acton, Associate of the Nuclear Policy Program at the Carnegie Endowment for International Peace, "Fukushima is not the worst nuclear accident ever but it is the most complicated and the most dramatic ... This was a crisis that played out in real time on TV. Chernobyl did not."Archived 18 April 2011 atWebCite
