Residents were urged to evacuate to "a school playground in Akuseki Island", a municipal official told AFP.

Akuseki is part of the Tokara island chain south of Kyushu region, which has been rattled by 1,031 quakes since June 21.

No major damage has been reported.

On Thursday, a 5.5 magnitude quake struck near Akuseki. The previous day a jolt of the same size was also recorded.

Seven of the 12 remote Tokara Islands are inhabited, with around 700 residents in total.

There was no tsunami risk from Thursday's quake, according to Ayataka Ebita, director of the earthquake and tsunami observation division of the Japan Meteorological Agency.

"In areas where the tremors were strong, there is an increased risk of collapsed houses and landslides," he told reporters.

"Please be aware of earthquakes of similar magnitude for the foreseeable future," he said.

A similar period of intense seismic activity in the Tokara area occurred in September 2023, when 346 earthquakes were recorded, according to the JMA.

Japan is one of the world's most seismically active countries, sitting on top of four major tectonic plates along the western edge of the Pacific "Ring of Fire".

The archipelago, home to around 125 million people, typically experiences around 1,500 jolts every year and accounts for about 18 percent of the world's earthquakes.

In 2011, a magnitude-9.0 quake triggered a tsunami that left 18,500 people dead or missing and caused a devastating meltdown at the Fukushima nuclear plant.

Quakes are extremely hard to predict, but in January a government panel marginally increased the probability of a major jolt in the Nankai Trough off Japan in the next 30 years to 75-82 percent.

The government then released a new estimate in March saying that such a "megaquake" and subsequent tsunami could cause as many as 298,000 deaths and damages of up to $2 trillion.

This week, the government released a report saying much more needed to be done to prepare for such a megaquake.

Some foreign tourists have held off coming to Japan due to unfounded fears fanned by social media that a major quake is imminent.

Causing particular concern is a manga comic reissued in 2021 which predicted a major disaster on July 5, 2025.

"We are aware that such tales are circulating, but that is a hoax," Ebita at the JMA said.

"With today's science and technology, it is not possible to predict earthquakes."