Earthquake Jolts Japan

A magnitude 5.1 earthquake shook eastern Japan on Sunday, swaying tall buildings in the capital Tokyo, the Japanese Meteorological Agency said.

National broadcaster NHK said there was no risk of tsunamis and there were no immediate reports of damage or injuries. The quake was centered northeast of the capital, NHK said.

Japan sits at the juncture of four tectonic plates, or moving slabs, of the earth's outer crust. It is one of the world's most earthquake-prone countries.

Tokyo's metropolitan area is home to some 35 million people, or about a quarter of Japan's population. A quake with an estimated magnitude 8.3 hit Tokyo in 1923, killing 142,000 people. Powerful quakes in 1703, 1782, 1812 and 1855 also caused vast damage in the city.

A powerful magnitude 7.2 earthquake struck northeastern Japan in August and injured at least 60 people, triggering a small tsunami and shaking skyscrapers as far away as Tokyo.

In 1995, a magnitude 7.3 quake in the western port city of Kobe killed 6,400 people. The depth and offshore location of Tuesday's quake helped limit the damage that might have occurred had it been centered under a city.