'Strong' 6.1-magnitude earthquake strikes off Japan coast

The shaker — which is classed as "strong" — was near the island of Okinawa, which has a population of more than 1.4 million.

Almost 16,000 people were killed by an earthquake off Japan's coast in 2011.

The under-sea tremor — which has a similar depth to Wednesday's quake — caused a tsunami, which led to the Fukushima Daiichi nuclear disaster.

The epicentre was in the Pacific Ocean — between Japan, China, South Korea and the Philippines, which has a population of 100 million.

The island of Taiwan — where 24 million people live — is very near.

There were no immediate reports of damage or injuries in the quake, which hit at a depth of 21 miles, about 166 miles east of Okinawa.

The US Geological Survey — which monitors earthquakes and volcanoes worldwide — said there is a "low likelihood" of casualties and damage.

There is a one in three chance up to 10 people could be killed — and only a 4 percent chance of more deaths.

The 1.4 million people who leave nearby will have felt "weak" effects.

A USGS spokesman said: "Overall, the population in this region resides in structures that are resistant to earthquake shaking — though vulnerable structures exist.

"The predominant vulnerable building types are low-rise concrete wall and light wood frame construction."

Japan lies on the notorious "Ring of Fire" — land around the Pacific Ocean regularly rocked by earthquakes and volcanoes.

A powerful 6.6-magnitude earthquake struck Indonesia — also in the region — back in May.

Two people were killed and more than 120 injured when an earthquake hit the Mediterranean last week.

A series of earthquakes in Wyoming has sparked fears a giant supervolcano in Yellowstone National Park could blow.