A strong earthquake of magnitude 6.0 struck near the east coast of Honshu, Japan, late on Saturday (October 4, 2025), the National Center for Seismology (NCS) reported. The quake, which occurred at 8:51 pm IST, was recorded at a depth of 50 kilometres, with its epicentre located at latitude 37.45°N and longitude 141.52°E.

Details from the National Center for Seismology

In an official post on X (formerly Twitter), the NCS confirmed the tremor details, stating: “EQ of M: 6.0, On: 04/10/2025 20:51:09 IST, Lat: 37.45 N, Long: 141.52 E, Depth: 50 Km, Location: Near East Coast of Honshu, Japan.”

Authorities have not reported any casualties or major damage so far, though local agencies continue to monitor the situation closely. The Japan Meteorological Agency (JMA) is assessing whether the quake could trigger aftershocks or tsunami activity along the Pacific coast.

Japan’s preparedness and seismic vulnerability

Japan sits along the Pacific Ring of Fire, one of the world’s most active seismic belts. The region is prone to frequent tremors due to the complex movement of tectonic plates beneath the Pacific Ocean. The country experiences thousands of earthquakes annually, most of them minor, though larger ones occasionally cause devastating tsunamis and destruction.

Thanks to its advanced early warning systems, stringent building codes, and dense seismic network, Japan is often able to mitigate the worst impacts of such natural disasters. Experts have described Japan’s seismic monitoring system as the most comprehensive in the world, allowing real-time analysis and alerts within seconds of detection.

Historical context: major past earthquakes

Japan has endured several powerful quakes over the decades, including the 2011 Tohoku earthquake and tsunami, which measured magnitude 9.0 and caused widespread devastation and the Fukushima nuclear disaster. Other significant quakes include the 2024 Noto earthquake, the 2004 Chuetsu earthquake, and the 1995 Great Hanshin earthquake, each of which caused considerable loss of life and infrastructure damage.

The frequency and magnitude of earthquakes in Japan underscore the constant seismic risk the nation faces. Scientists continuously study these events to improve forecasting models and enhance structural resilience in high-risk zones.

How Japan measures quakes: the Shindo scale

Unlike most countries that use the Richter or moment magnitude scale, Japan employs the Shindo scale to measure the intensity of ground shaking at various locations. The Shindo system reflects the perceived impact of a quake—ranging from minor tremors felt indoors to violent shaking that can cause widespread structural damage.

Comparable systems include the Modified Mercalli scale in the United States, the Liedu scale in China, and the European Macroseismic Scale (EMS) used across Europe.

No immediate tsunami warning

As of late Saturday, there were no official tsunami warnings or alerts issued for the eastern coast of Japan. However, authorities have urged residents to remain cautious and follow any instructions from local disaster management offices, particularly in coastal areas.

Japan’s Meteorological Agency continues to evaluate seismic data and monitor for any potential aftershocks in the coming hours.

Conclusion

While Saturday’s magnitude 6.0 earthquake near Honshu’s east coast caused no reported casualties, it serves as another reminder of Japan’s ever-present vulnerability to seismic activity. The nation’s preparedness and extensive monitoring network remain key in preventing large-scale loss of life during such natural events.