Photo/Illutration The “Tokara Theory” circulating online speculates that a series of recent earthquakes in Akusekijima and other Tokara islands will precede the long-anticipated Nankai Trough megaquake. (Provided by Kyushu Asahi Broadcasting Co.)

The nation’s top earthquake expert has dismissed claims circulating online that the recent chain of intense seismic activity off Kagoshima Prefecture's coast signals an impending Nankai Trough megaquake, saying there is no scientific evidence to support the connection.

“This is my personal view, but there is no study or data showing a causal link between earthquakes in the Tokara island chain and those in other regions,” said Naoshi Hirata, a seismologist and professor emeritus at the University of Tokyo, on July 7.

Hirata made the comment following a regular meeting of the government expert panel he chairs, which assesses the risk of the long-expected Nankai Trough megaquake expected to occur within the next three decades.

More than 1,600 tremors have been recorded in the Tokara region since June 21, ranging from barely perceptible ones to those strong enough to topple items off shelves and cause a fissure.

This prompted social media speculation under the so-called “Tokara Theory”—a hypothesis suggesting that the earthquakes in the Tokara area are a precursor to major seismic events in relatively distant parts of Japan. 

The largest tremor recorded in the recent Tokara swarm was below a magnitude 6.

Hirata emphasized that earthquakes of this scale are not expected to affect areas as far as the main islands of Kyushu, Shikoku or Honshu—regions predicted to be impacted by a Nankai Trough earthquake.

While downplaying the connection to a larger seismic event, Hirata reiterated the importance of general disaster preparedness.

“Japan is a country where earthquakes occur frequently,” he said. “You should always be prepared to protect your life.”

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