Confusion erupted in Japan after the Japan Meteorological Agency (JMA) mistakenly estimated a magnitude 6.9 earthquake near the Kamchatka Peninsula, Russia, as a massive 9.9 on October 16, issuing alerts across a wide area of eastern Japan before canceling them about eight minutes later.

At around 12:40 p.m. that day, the JMA issued an "Emergency Earthquake Alert," warning that strong shaking was expected across eastern Japan, stretching from Hokkaido to the Tohoku, Kanto, Hokuriku, Tokai, and Izu Islands.

At the time, the agency estimated the earthquake's magnitude at 9.9.

Earthquake alerts went off simultaneously on the mobile phones of people in the affected regions.

About eight minutes later, the agency sent out another notification—also in the form of an emergency earthquake alert—canceling the previous warning.

The earthquake's magnitude was revised to 6.9.

It is highly unusual for the weather agency to issue an emergency earthquake alert and then completely retract it.

During a press conference held in the afternoon, the JMA officially apologized for the erroneous report, explaining that the initial cause was incorrectly determining the epicenter to be the Kuril Islands (Chishima Islands) and overestimating the magnitude at 9.9.

The agency added that it is currently investigating the reason behind the overestimation.

Asked during the press conference whether the overestimation could be related to recent sequential cyberattacks across various sectors, Ebita Ayataka, head of the JMA's Earthquake and Tsunami Observation Division, responded, "According to what I have heard from system personnel, there was no cyberattack."

Although the earthquake warning was lifted, the alert issued across a vast region left citizens trembling with anxiety and caused widespread confusion.

Japanese media reported that as users rushed to social media all at once, X (formerly Twitter) timelines temporarily failed to load, and search services such as Yahoo became inaccessible.

According to the JMA, apart from a seismic intensity of 1 detected in Hakodate, Hokkaido, no strong shaking was observed within Japan as a result of the earthquake.

The agency added that there was no risk of a tsunami.