TOKYO — Japan is on high alert after a series of strong earthquakes off the country’s northeastern coast, prompting megaquake advisories, tsunami warnings and ongoing aftershocks as authorities warn of elevated seismic risk this week.
On Monday night, a magnitude 7.5 earthquake struck offshore near Aomori Prefecture in northern Japan, producing intense ground shaking measured at upper-6 on Japan’s seismic scale and injuring dozens of people, with light structural damage reported across the region. Earlier tsunami warnings were issued for coastal prefectures including Hokkaido, Aomori and Iwate, though these were later downgraded after observed waves were relatively small.
In response to the strong quake, the Japan Meteorological Agency (JMA) issued its first-ever megaquake advisory in this context, a special alert indicating that conditions along the Japan Trench and nearby subduction zones could be favourable for another large earthquake in the coming days. The advisory currently covers dozens of municipalities from Hokkaido down to Chiba Prefecture, urging residents to stay vigilant, be prepared for emergency actions and monitor updates.
Adding to the seismic unrest, a separate magnitude 6.7 earthquake struck on Friday morning off the coast of Aomori, again triggering a tsunami advisory for parts of northern Japan, with potential waves of up to 1 metre along sections of the Pacific coast — including Hokkaido, Aomori and Miyagi — though no major damage has been immediately reported.
Authorities have emphasised that tsunami advisories and warnings remain possible for days after a major quake, and that aftershocks — including quakes registering magnitudes in the 5-6 range — continue to be monitored. Emergency services and local governments have urged residents in affected coastal communities to review evacuation routes, prepare emergency kits, and stay informed through official channels such as the JMA and NHK broadcasts.
Context & Safety Recommendations:
- Japan lies on the Pacific “Ring of Fire,” making it one of the most earthquake-prone nations globally.
- The megaquake advisory system is designed to warn of increased risk conditions — not precise predictions — for a larger tremor in the near term.
- Residents in northern and northeastern coastal prefectures are being advised to:
- stay away from shorelines during tsunami advisories
- prepare emergency supplies (water, food, lights, chargers)
- secure furniture and essentials to reduce secondary injury risk during aftershocks.
Summary: Japan is currently facing heightened seismic alert levels following multiple significant earthquakes, including the powerful magnitude 7.5 event and subsequent strong tremors. While major tsunamis have not materialised, authorities have maintained elevated vigilance and issued special advisories indicating the region’s elevated risk for further large earthquakes through mid-December.