No major damage has been reported from the series of tremors, but the Japan Meteorological Agency held an emergency news conference after a magnitude 5.5 quake was registered around 3:30 pm in the Tokara island chain, south of Kyushu region.

"Seismic activity has been very active in the seas around the Tokara island chain since June 21," Ayataka Ebita, director of the earthquake and tsunami observation division, told reporters.

"As of 4:00 pm today, the number has exceeded 900," he said, adding the agency could not tell when quakes would end.

Tokara village said on its website residents haven't been able to sleep and were tired.

"It feels like it's aways shaking," one resident told regional broadcaster MBC. "It's very scary to even fall asleep."

"It's not clear when all this will end. I should think about whether to evacuate my kids," another resident said.

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

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

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, experiences around 1,500 jolts every year and accounts for about 18 percent of the world's earthquakes.

The vast majority are mild, although the damage they cause varies according to their location and the depth at which they strike.

Nearly 600 people died after a massive earthquake hit the Noto Peninsula in central Japan on New Year's Day in 2024.