Bangkok Post / AFP
May 30, 2015

TOKYO — A 7.8-magnitude earthquake struck off the Japanese coast on Saturday, geologists said, shaking buildings in Tokyo and setting off car alarms.

Despite the huge power of the quake, there was no risk of a tsunami, The Pacific Tsunami Warning Centre reported.

Residential buildings swayed for around a minute as the quake built in intensity at around 8.30pm local time, an AFP correspondent reported.

The epicentre was 676 kilometres below the Earth's surface. It was centred on a remote spot in the Pacific Ocean around 870 kilometres south of Tokyo, the US Geological Survey said.

Both runways at Narita Airport, the main international gateway to Tokyo, were temporarily closed while inspections were carried out.

It was the second sizable shake Tokyo has had this week, after a much less powerful — but far shallower — quake hit close to the capital on Monday.

Japan sits at the meeting place of four tectonic plates and experiences around 20 percent of the world's most powerful earthquakes every year.

Offshore quake rattles Tokyo | Bangkok Post: news