Japanese researchers say a massive earthquake could occur off a peninsula to the east of Tokyo, in an area separate from the one that triggered the Great Kanto Earthquake of 1923.
The Geospatial Information Authority of Japan reported to a government panel on Wednesday that analysis of global positioning system data shows that the tip of the Boso Peninsula has been moving about 3 centimeters north each year since 1997.
The authority says quake-causing strain may be building up in the area, where a marine tectonic plate slides under a continental plate.
The situation is similar around the Miura Peninsula to the south of Tokyo, near Yokohama.
Pressure there was released in the 1923 earthquake, but the area off Boso Peninsula has not had a major quake for at least 300 years.
Researcher Takuya Nishimura says an earthquake occurring in this zone could have a magnitude of around 8. He says the authority will continue its analysis to increase the accuracy of its estimations.