Japan Issues Rare Quake Advisory as Tsunami Alerts Rise Across the Region

Japan has issued a rare special advisory warning residents in northeastern coastal areas to prepare for the possibility of an even more powerful earthquake following a magnitude 7.7 quake that struck off the coast of Iwate prefecture on Monday, April 20, 2026.

The advisory, issued jointly by the Cabinet Office and the Japan Meteorological Agency (JMA), indicates a one percent chance of a mega-quake occurring in the region within the next week or so. Officials emphasized that the advisory is not a prediction but a precautionary measure urging residents to enhance their preparedness while continuing daily life.

Japan issued an advisory on Monday for an increased risk of a possible mega-quake in northern coastal areas, induced by a major earthquake earlier in the day.

The Associated Press

Officials said the advisory is not a quake prediction but urged residents to raise their preparedness, such as having emergency food and a go bag, while continuing their daily lives.

CBC News

The advisory follows a similar alert issued in December after another major quake, though no significant subsequent earthquake occurred at that time. The current warning comes as seismic activity remains elevated along the Chishima trough, a known subduction zone off Japan’s northeastern coast where tectonic plates converge.

On Monday, the 7.7 magnitude earthquake struck at 4:53 p.m. Local time, shaking buildings as far south as Tokyo and prompting immediate tsunami warnings for waves up to three metres high. Although the tsunami alert was later downgraded after waves of up to 80 centimetres were recorded, authorities maintained vigilance for potential aftershocks and larger seismic events.

Prime Minister Sanae Takaichi confirmed that the government activated a crisis management team to assess the earthquake’s impact and coordinate regional preparedness efforts. She urged the public to heed official guidance and remain ready for possible future developments.

The quake hit on Monday at 4:53pm (07:53 GMT) in waters off Iwate prefecture on the Pacific coast, according to the Japan Meteorological Agency (JMA). It was felt across a wide area, shaking buildings in Tokyo, hundreds of kilometres to the south.

Al Jazeera

As of Tuesday, April 21, 2026, no major damage or casualties have been reported from the initial quake or its immediate aftermath. However, the special advisory remains in effect, reflecting ongoing concern about the potential for a larger seismic event in the coming days.

Japan continues to monitor the situation closely, with the JMA and local authorities providing regular updates. Residents in affected areas are advised to stay informed through official channels and maintain emergency readiness without altering normal routines unless directed otherwise.