2011 Tōhoku earthquake and tsunami facts for kids

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2011 Tōhoku earthquake and tsunami
Smoke from the Sendai Nippon Oil refinery
UTC time	2011-03-11 05:46:24
ISC event	16461282
USGS-ANSS	ComCat
Local date	March 11, 2011 (2011-03-11)
Local time	14:46 JST
Duration	6 minutes
Magnitude	9.0–9.1 (M_w)
Depth	29 km (18 mi)
Epicenter	38°19′19″N 142°22′08″E / 38.322°N 142.369°E / 38.322; 142.369
Type	Megathrust
Areas affected	Japan (shaking, tsunami) Pacific Rim (tsunami)
Total damage	$360 billion USD
Max. intensity	IX (Violent)
Peak acceleration	2.99 g
Peak velocity	117.41 cm/s
Tsunami	Up to 40.5 m (133 ft) in Miyako, Iwate, Tōhoku
Landslides	Yes
Foreshocks	List of foreshocks and aftershocks of the 2011 Tōhoku earthquake
Aftershocks	13,386 (as of 6 March 2018)
Casualties	15,897 deaths, +2 (Overseas), 6,157 injured, 2,533 people missing

The 2011 Tōhoku earthquake and tsunami was a 9.0-magnitude earthquake followed by tsunami waves. It was measured at 8.4 on the JMA seismic intensity scale. The earthquake happened 130 kilometres (81 mi) off Sendai, Miyagi Prefecture, on the east coast of the Tōhoku of Japan, on March 11, 2011 at 05:46:23 UTC. It was at a depth of 24.4 km (15.2 miles). It was the most powerful earthquake to hit Japan in recorded history. It was also the fourth most powerful earthquake on Earth since modern record-keeping began in 1900.

On 10 February 2015, the Japanese National Police Agency report confirmed 15,890 deaths, 6,152 injured, and 2,590 people missing.

Earthquake
Tsunami
Effects
Other help
Images for kids
See also

Earthquake

Days before the main earthquake, there were several foreshocks. 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) from Tokyo. A 7.7 aftershock happened 30 minutes following the first quake. There have been more than 600 aftershocks bigger than magnitude 4.5 or more.

The earthquake damaged buildings and started fires. The Shinkansen high speed bullet trains were stopped and Haneda Airport was closed after the quake. Various train services around Japan were also stopped. Hundreds of flights to Japan were cancelled due to the earthquake and tsunami, affecting many people. A large fire broke out at an oil refinery in Ichihara, Chiba prefecture.

The nuclear power plants shut down automatically. At first the Japanese Prime Minister said that no radioactive material leaked. About 51,000 people were moved away from the nuclear reactor at the Fukushima Daiichi Nuclear Power Plant in Fukushima city when its cooling system failed. There are fears that the nuclear reactor might meltdown.

Tsunami

Damage at Point Hachinohe

The earthquake started a tsunami warning for Japan's Pacific coast and other countries, including New Zealand, Australia, Russia, Guam, Philippines, Indonesia, Papua New Guinea, Nauru, Hawaii, Northern Mariana Islands (USA) and Taiwan. The tsunami warning issued by Japan was the most serious on its warning scale. It warned that the wave could be as much as 10 meters high. A 0.5 meter high wave hit Japan's northern coast. Kyodo news agency reported a four-metre-high tsunami hit the Iwate Prefecture in Japan. Miyagi Prefecture was flooded, with waves carrying buildings and cars along as they travelled inland. In some areas the waves reached 10 km inland.

At 9:28 p.m (HST) the National Weather Service issued a tsunami warning until 7 a.m. for all of Hawaii. Tsunami waves were expected to arrive in Hawaii at 2:59 am local time. A wave two meters high reached California, after travelling across the Pacific Ocean at a speed of 500 kilometres per hour. A man in California was drowned after being swept into the ocean while trying to take a photograph of the tsunami wave.

Effects

People getting off a train due to the closure of the railway network

Deaths–Injured–Missing

The Japanese National Police Agency has officially confirmed 15,890 deaths, 6,152 injured, and 2,590 people missing across 18 prefectures, as well as over 126,000 buildings damaged or destroyed.

Nuclear disaster

The Fukushima nuclear disaster began on March 11 2011, just hours after the initial wave. The connection to the electrical grid was broken. All power for cooling was lost and reactors started to overheat. There was a partial core 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 biggest nuclear accident after the Chernobyl disaster, but more complex as all reactors are involved.

There were 4.4 million households that had their electricity supply cut off, including 11 nuclear power plants.

Geophysical impact

The quake moved parts of northeast Japan as much as 2.4 meters (7.9 ft) closer to North America, making parts of Japan's land "wider than before," according to geophysicist Ross Stein. Areas of Japan closest to the epi-center shifted the most.

The Pacific plate itself may have moved westwards by up to 20 m (66 ft). 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.

According to Italy's National Institute of Geophysics and Volcanology, the earthquake shifted the Earth's axis by 25 centimeters (9.8 in). This deviation led to a number of small planetary changes, including the length of a day and the tilt of the Earth. The speed of the Earth's rotation increased, shortening 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. Due to the 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.

Transport

The Tōhoku Expressway, which serves northern Japan, had to be closed due to cracks on the roads. 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.

Television broadcast

In response to the great disaster, Emperor Akihito directly addressed his subjects in a television broadcast. This was the first time any emperor used television in this way.

Other help

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.

Images for kids

A seismogram recorded in Massachusetts, United States
A visual depiction of the type of faulting that caused the main tremor, low-angle thrusting on a west-dipping fault plane
Soil liquefaction in Kōtō, Tokyo
Satellite image shows snowfall on agricultural fields in Sendai area. See § Weather conditions paragraph for details.
Land subsidence and soil liquefaction at Shin-Urayasu Station in Urayasu, Chiba, near Tokyo
NOAA tsunami energy map
Water column height on 11 March 2011 at DART Station, 690 NM southeast of Tokyo
The city of Rikuzentakata, Iwate Prefecture, suffered extensive damage from the tsunami, with almost the entirety of the lower area of the city being destroyed.
Tsunami flooding on the Sendai Airport runway
A Bonin petrel trapped in tsunami debris on Midway Atoll before being rescued
Fishing boats that were moved to higher ground in anticipation of tsunami arrival, in Pichilemu, Chile
Japanese Boat washed ashore the Oregon Coast, United States
Rescue team searching for survivors. Snow arrived minutes before or after the tsunami, depending on locations.
Panorama of Rikuzentakata
A fire that broke out in Tokyo
Snowfall in Ishinomaki, 16 March.
Ship and crane damage at Sendai port
Fire at the Cosmo Oil refinery in Ichihara
An aerial view of the smoke from the Sendai Nippon Oil refinery
A loose cow roaming through Namie, Fukushima after the area was evacuated
Remains of Shinchi Station
Damage to a traditional lantern at Tokiwa shrine in Mito City
Emergency vehicles staging in the ruins of Otsuchi, Japan following the tsunami
Anti-nuclear protest following the disaster