7.3 earthquake

The 7.3-magnitude quake was felt strongly in Tokyo, but a tsunami warning has not been issued.

There are reports of about 50 people injured, officials say, and almost one million homes are without power.

The quake struck near the epicentre of a 2011 earthquake which triggered a tsunami and killed over 18,000 people.

That tsunami caused a nuclear accident at the Fukushima Daiichi Nuclear Power Plant - the world's most severe nuclear accident since the Chernobyl disaster in 1986.

The quake occurred at a depth of 10km in an area 168km south-southeast of the city of Ternate, the USGS said.

Indonesia's meteorology agency (BMKG) recorded the quake at 7.2 magnitude and was not in danger of causing a tsunami.

The country's disaster mitigation agency said on Twitter a woman in South Halmahera died due to the quake, without giving further details.

Within less than four hours since the main quake, the disaster agency recorded at least 30 aftershocks, it added.