Chilling megaquake warning for Japan

Authorities are warning that Japan as it an increased risk of a megaquake striking, which could devastate the archipelago.

A devastating “megaquake” is increasingly likely to rock Japan, authorities are warning.

The caution was issued after a powerful earthquake with a magnitude of 7.1 shook southern Japan on Thursday. No major damage was reported and only relatively minor tsunami waves lashed the coast.

Speaking at a press conference later that day, Japanese Meteorological Agency official Shinya Tsukada warned that there was an increased risk of a “major earthquake” in Japan.

It’s the first time such a warning has been issued.

There’s an increased risk of a megaquake in Japan, authorities warn. Picture: iStock

The agency clarified that a major earthquake was not necessarily imminent, but the chances were higher than normal.

Sitting on top of four major tectonic plates along the western edge of the Pacific “Ring of Fire”, Japan is one of the world’s most tectonically active countries.

A major source of quakes is the Nankai Trough, about 900km east of the island of Honshu.

Experts say that there is a 70-80 per cent chance of a magnitude 8 or 9 earthquake striking in the trough over the next 30 years.

The Japanese archipelago, home to around 125 million people, experiences around 1500 jolts every year and accounts for around 18 per cent of the world’s earthquakes.

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

Still, even large quakes usually cause little damage thanks to special construction techniques and strict building regulations in the world’s number four economy.

At least 318 people were killed when an earthquake hit the Noto peninsula on the Sea of Japan side of Honshu on New Year’s Day.

Buildings burning in the city of Wajima, Ishikawa prefecture on January 1, 2024, after a 7.5 magnitude earthquake struck the Noto region. Picture: AFP

The January 1 quake and its aftershocks toppled buildings, caused fires and knocked out infrastructure.

Japan also routinely holds emergency drills to prepare for a major quake. It is haunted by the memory of a colossal 9.0-magnitude undersea quake off northeastern Japan in March 2011, which triggered a tsunami that left around 18,500 people dead or missing.

It sent three reactors into meltdown at the Fukushima nuclear plant, causing Japan’s worst post-war disaster and the most serious nuclear accident since Chernobyl.

In March 2022, a 7.4-magnitude quake off the coast of Fukushima shook large areas of eastern Japan, killing three people.

The capital Tokyo was devastated by a huge earthquake a century ago in 1923.

- with AFP