Japan lifts its megaquake advisory but urges caution

Japan has lifted a megaquake advisory for the country's northeastern coast, one week after a magnitude 7.5 earthquake struck off northern Japan that officials say had caused an increased risk of a subsequent major quake.

The lifting means residents in the designated area under the advisory are no longer asked to sleep in their day clothes, with helmets, shoes and grab bags at their bedside in case a magnitude 8.0 or larger quake hits the area.

At a joint news conference on Tuesday, officials at the Japan Meteorological Agency and Cabinet Office said the probability of a megaquake has somewhat decreased, but the lifting did not mean the risk had disappeared, urging residents to maintain adequate levels of vigilance and preparedness.

The agency issued the so-called megaquake advisory last Monday after the magnitude 7.5 quake struck off the eastern coast of Aomori, the northernmost prefecture of Japan's main island of Honshu, and just south of the northern island of Hokkaido, leading to mild damage in the region.

The earthquake caused more than 40 mostly mild injuries and damaged dozens of homes, according to the Fire and Disaster Management Agency. Tsunami alerts and advisories were issued and waves of up to 70 centimetres were recorded in parts of the region, but no tsunami damage was reported.

Officials said municipalities and residents reacted calmly to the advisory and there was no panicking.

In the summer of 2024, when Japan issued a first-ever "Nankai Trough" megaquake advisory for the southern half of the country's Pacific coastline, the ambiguity of that warning led to panic buying of emergency food, event cancellations and business closures.

The mechanism for issuing advisories for the Hokkaido-Sanriku area was introduced in 2022 as a lesson from the 2011 disaster, when a magnitude 9.0 quake and subsequent tsunami devastated Japan's northeastern coast.