The US Geological Survey says the magnitude 6.6 quake struck near the
northern city Sapporo, at a depth of 66-kilometres.
It was followed by a 5.3 aftershock.
Local broadcaster NHK is reporting there's no initial damage, although some
households have suffered blackouts.
The island is still recovering from a major quake in June, where a deadly
tremor rocked the central Osaka region, killing five people and injuring over
350.