Japan Issues Rare Megaquake Warning 2025 After Powerful 7.5 Earthquake Off Aomori

December 11, 2025 — Japanese authorities have issued a rare megaquake advisory, the highest-level warning in years, urging immediate preparedness across northern and central regions, including the notorious Nankai Trough.

The alert follows a magnitude 7.5 earthquake that struck off the coast of Aomori Prefecture, the northernmost prefecture on Japan’s main island of Honshu.

Aomori Earthquake: What We Know So Far

• Magnitude 7.5
• 34 people injured (mostly minor)
• Minor damage to roads and buildings
• Small tsunami waves up to 1 meter

Why Japan Issued the Megaquake Warning

Experts now fear the quake may have increased stress along the Nankai Trough subduction zone, which is capable of producing magnitude 8–9 events.

While the immediate risk remains low, the government has raised long-term probabilities and is calling for heightened readiness.

What Residents Should Do Now

• Prepare emergency kits for 7–14 days
• Secure heavy furniture
• Know your evacuation routes

Sources: The Guardian, NHK, Japan Meteorological Agency, USGS

Latest Japan megaquake warning 2025 updates will be posted here as soon as new information becomes available.