The first, which had a magnitude of 6.6, occurred at 0902 (0002 GMT) about 120km (75 miles) north of the city of Ternate, the US Geological Survey said. A few minutes later, a 7.2-magnitude quake hit Hokkaido's coast, 220km (135 miles) east of the capital, Sapporo. There have so far been no reports of casualties from either country. The Japan Meteorological Agency has issued a warning for a 50cm (20-inch) tsunami along the eastern coast of Hokkaido and the north-eastern coast of the country's main island of Honshu. But the warning was later cancelled.