Factbox: The history of earthquakes in Japan
The biggest earthquake to hit Japan since records began 140 years ago struck the northeast coast on Friday, triggering a 10-meter tsunami that swept away everything in its path. Following are facts about Japan and earthquakes.
* The US Geological Survey located the 8.9 magnitude quake at a depth of 15.1 miles and 81 miles east of Sendai, on the main island of Honshu.
* Japan, situated on the "Ring of Fire" arc of volcanoes and oceanic trenches which partly encircles the Pacific Basin, accounts for about 20 percent of the world's earthquakes of magnitude 6 or greater.
-- Tokyo, with a population of 12 million, sits on the junction of four tectonic plates: the Eurasian, North American, Philippine and Pacific. The sudden bending or breaking of any plate can trigger an earthquake.
* A tremor occurs in Japan at least every five minutes, and each year there are up to 2,000 quakes that can be felt by people.
SOME MAJOR QUAKES IN JAPAN:
* The Great Kanto earthquake of Sept. 1, 1923, which had a magnitude of 7.9, killed nearly 143,000 people in the Tokyo area.
-- There was extreme destruction in the Tokyo-Yokohama area from the earthquake and subsequent firestorms, which burned about 381,000 of the more than 694,000 houses that were partially or completely destroyed. Although often known as the Great Tokyo Earthquake (or the Great Tokyo Fire), the damage was apparently most severe at Yokohama.
-- A tsunami was generated in Sagami Bay with wave heights as high as 12m on O-shima and 6m on the Izu and Boso Peninsulas.
-- Seismologists have said another such quake could strike the city at any time.
* On March 2, 1933, on Japan's northeast Pacific coast, a magnitude 8.1 quake in the area killed more than 3,000 people. The quake struck about 290 km (180 miles) off the coast of Honshu, most of the casualties and damage were caused by a large tsunami, instead of directly from the earthquake itself.
* On June 28, 1948 an earthquake measuring 7.3 killed 3,769 people at Fukui 28 miles northeast of Kyoto.
* On Jan. 16, 1995, an earthquake with a magnitude of 7.3 hit central Japan, devastating the western port city of Kobe. It was the worst earthquake to hit Japan in 50 years, killing more than 6,430 and causing an estimated $100 billion in damage -- the most expensive natural disaster in history.
* On Oct. 23, 2004, a 6.8 magnitude quake struck the Niigata region, about 250 km (150 miles) north of Tokyo, killing 65 people and injuring 3,000.
* On March 25, 2007, a 6.9 magnitude quake struck the Noto peninsula in Ishikawa prefecture, about 300 km west of Tokyo, killing one person, injuring more than 200 and destroying hundreds of homes.
* On July 16, 2007, a 6.8 magnitude quake struck Niigata prefecture, about 250 km (150 miles) northwest of Tokyo, killing 11 people and injuring 1,950. The tremor caused radiation leaks at the world's largest nuclear plant, which officials said were within safety regulations and posed no threat to the environment. The leaks nonetheless reignited fears about nuclear safety in the quake-prone country.
* On Aug. 11, 2009 a 6.5-magnitude earthquake centered about 150 km (90 miles) southwest of Tokyo jolted the city and surrounding areas, disrupting transport and closing a nuclear plant for safety checks.
* On March 14, 2010 a strong earthquake with a preliminary magnitude of 6.6 jolted northern Japan shaking buildings in the capital Tokyo some 240 km (150 miles) away. The epicenter was about 40 km (25 miles) beneath the ocean off Honshu, Japan's main island, the Japan Meteorological Agency (JMA) said.
* On Nov. 30, 2010 a deep earthquake with a magnitude of 6.9 hit islands off the east coast of Japan, the JMA said, causing build