Japan on High Alert: Megaquake Possibility Looms After Recent 7.5 Quake

Tue Dec 09 2025 18:42:08 GMT+0200 (Eastern European Standard Time)

Following a magnitude 7.5 earthquake, Japan’s authorities warn of a potential megaquake, awakening fears of devastating seismic events that could strike within the next three decades.

A recent 7.5 magnitude earthquake in northeastern Japan has prompted officials to raise alarms about the potential occurrence of a megaquake, a devastating seismic event that could lead to substantial loss of life and property damage. Authorities urge residents in several prefectures to remain vigilant and prepare for emergencies, despite not issuing a formal evacuation order.

After a magnitude 7.5 earthquake struck north-eastern Japan on Monday, authorities again warned of the possibility of a future megaquake.

It means that thoughts in Japan are turning to the 'big one' - a once-in-a-century quake.

In September, Japan's earthquake investigation panel said there was a 60-90% chance that a megaquake would occur in the Nankai Trough - an area of seismic activity which stretches along Japan's Pacific coast - within the next 30 years.

In April, authorities had warned that a megaquake had the potential to trigger a tsunami of more than 20m (66ft) which could hit parts of Tokyo and other prefectures. They predicted that there would be around 300,000 deaths and trillions of dollars in economic damage.

Officials urged residents in seven prefectures from Hokkaido in the north to Chiba in central Japan to stay on high alert for a potential megaquake.

This is a vast area with millions of people.

A government official said there was a possibility that 'a large-scale earthquake with a magnitude of 8 or higher could occur as a follow-up earthquake' in the region.

Authorities also told people to check evacuation routes, secure furniture, and prepare emergency kits, including food, water and portable toilets.

However, an evacuation order was not issued.

Japan's director for disaster management said at a news conference that global earthquake data suggests there's a possibility, not a prediction, of a larger tremor to come.

Officials said the possibility of a larger quake occurring is about one in 100.

Japan is a country used to earthquakes. It sits on the Ring of Fire and, as a result, experiences about 1,500 earthquakes a year.

The vast majority do little damage, but there are some - like the one which struck in 2011 measuring magnitude 9.0, sending a tsunami into the north-east coast and killing more than 18,000 people.

However, the one that authorities fear may strike in this more densely populated region to the south could - in the absolute worst-case scenario - be even more deadly.

Earthquakes along the Nankai Trough have already been responsible for thousands of deaths, with the last megaquake occurring almost 80 years ago.

Scientists are apprehensive, but as of now, further predictions remain speculative.