Japan's Earthquake Warning Raises Alarms: Is the Big One Approaching?

Tue Dec 09 2025 18:42:20 GMT+0200 (Eastern European Standard Time)

After a 7.5 magnitude quake jolted northeastern Japan, experts warn of a possible megaquake that could hit in the near future. Authorities urge residents to prepare as fears of seismic disaster grow.

In the aftermath of a significant 7.5 magnitude earthquake in northeastern Japan, experts are alerting citizens of a potential megaquake that may follow. Historical data suggests a high probability of a major seismic event occurring in the Nankai Trough region within the next three decades. Officials have advised residents in multiple prefectures to stay vigilant and prepare for emergency situations, although no evacuation orders have been issued. The discussion turns to the unpredictability of earthquakes and the challenges in forecasting such devastating natural events.

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.

Not according to Robert Geller, professor emeritus of seismology at the University of Tokyo. When authorities issued a megaquake warning last year, after a 7.1 quake struck southern Japan, Prof Geller told the BBC that the warning had 'almost nothing to do with science'. The advisory was 'not a useful piece of information', he said.

While the warning system was introduced in an attempt to prevent disasters, readings suggest that predicting earthquakes remains an elusive science.

However, the JMA reassured that while the likelihood of a significant quake is higher than normal, this does not guarantee that a catastrophic earthquake will strike in the immediate future.