Total of 21 quakes above 4.0 magnitude hit Japan: Met office

Map of Japan locating the epicentre of a 7.5-magnitude earthquake on 1 JanuaryAFP

A succession of 21 earthquakes registering 4.0 magnitude or stronger struck central Japan in just over 90 minutes on Monday, the Japan Meteorological Agency said.

The strongest jolt measured 7.6, it said. The quakes prompted tsunami warnings and authorities urged people in the area to move to higher ground.