Over 800 earthquakes in 11 days: What's happening on Japan’s Tokara Islands

More than 800 earthquakes have rattled a remote island chain in southern Japan over the past two weeks, leaving residents sleepless and worried, according to the Japan Meteorological Agency (JMA).

The quakes began around June 21 in the seas near the Tokara Islands, south of Kyushu, Japan’s main southern island. A magnitude 5.5 earthquake struck the region on Wednesday afternoon, prompting an emergency press conference by JMA officials.

“As of 4pm today, the number of earthquakes has exceeded 900,” said Ayataka Ebita, head of the agency’s earthquake and tsunami division. He urged residents to be ready to take shelter or evacuate in case stronger quakes strike.

No major damage has been reported so far, but the constant shaking has taken a toll on residents. Local officials said people in Tokara village are exhausted due to a lack of sleep. “It feels like it’s always shaking,” one resident told local media. Another said they were thinking about evacuating their children.

Seismic activity peaked on 23 June, with 183 earthquakes recorded in a single day. The number dropped for a few days but rose again later, reaching 98 on 29 June and 62 on 30 June. In comparison, a previous spike in September 2023 saw 346 earthquakes in the same area.

Seven of the 12 Tokara Islands are inhabited, with a total population of around 700. Experts believe the area’s unique underwater geography makes it more prone to pressure build-up, which can lead to frequent quakes.

Japan is one of the most earthquake-prone countries in the world, located on four major tectonic plates along the Pacific “Ring of Fire.” The country experiences around 1,500 tremors a year—about 18 per cent of the world’s total.

Earlier this year, nearly 600 people died after a powerful quake struck the Noto Peninsula. In 2011, more than 18,000 people were killed when a massive magnitude 9.0 quake triggered a devastating tsunami and the Fukushima nuclear disaster.

This week, the Japanese government warned that more must be done to prepare for a possible “megaquake” along the Pacific coast. Experts now estimate a 75–82 per cent chance of a major earthquake hitting the Nankai Trough within the next 30 years. A March 2025 government report said such a quake and tsunami could kill up to 298,000 people and cause damage worth up to $2 trillion.