A warning of the Earthquake Early Warning issued by the Japan Meteorological Agency was cancelled. The Mainichi Shimbun reported it as the first cancellation and said the magnitude of the quake had been overestimated as M9.9. The area affected is said to be wide, from Hokkaido to the Tokai region. The agency apologized and denied a cyberattack. The cause is under investigation.
This bears directly on trust in disaster-prevention information, and the cause and the measures to prevent a recurrence will be the focus from here.
It is a chance to confirm with your family, in ordinary times, how to act when you receive a warning.
The agency admitted the erroneous estimate and apologized, and denied a cyberattack, but the cause is under investigation.
Mainichi Shimbun, Jev tally (many reports related to the Japan Meteorological Agency)
Earthquake Early Warning Cancelled for the First Time; Magnitude Overestimated as 9.9, Meteorological Agency Apologizes
The Japan Meteorological Agency cancelled a warning issued across a wide area from Hokkaido to the Tokai region. A cyberattack was ruled out, and the cause is still being investigated.
By the night of the 16th, it was being reported one after another that the Japan Meteorological Agency had cancelled an Earthquake Early Warning alert it had issued. The Mainichi Shimbun called it the “first cancellation of a warning” and reported that the agency had overestimated the magnitude of the quake as 9.9. The area covered was said to be wide, stretching from Hokkaido to the Tokai region, and the agency has apologized.
The central question is the cause. Multiple reports say the agency denied a “cyberattack,” but why such an off-the-charts figure was produced is under investigation, and it has not been disclosed at which stage of the system the problem arose. We will have to wait for analysis by experts and the agency's final explanation.
By Jev's tally, 17 articles covered the matter, with headlines framed around angles such as “no cyberattack” and “wide area from Hokkaido to Tokai.” The volume of coverage is large, but no new facts have been added; the core comes down to three points: the cancellation, the apology and the ongoing investigation into the cause.
The Earthquake Early Warning is a system that prompts people to take protective action before strong shaking arrives. A magnitude of 9.9 is a scale without precedent in recorded observation, and a figure at which a giant tsunami would also be expected if it actually happened. For that reason, a wrong estimate not only causes public anxiety but could undermine trust in the next real warning. How users, transport operators and local governments acted between the warning and its cancellation could not be confirmed within the range of this paper's collection.
There are three points readers should keep in mind. First, the cancellation is a correction of an erroneous estimate, and the material collected for this paper includes no report that a huge earthquake actually occurred. Second, because the cause is unresolved, the substance of any measures to prevent a recurrence is not yet visible. Third, the cyberattack theory has been denied by the agency, and baseless assertions should be avoided. Going forward, the focus will be on when the results of the investigation are published and on a review of how those who received the warning responded. It is also worth noting that the longer the agency's explanation is delayed, the more readily speculation spreads. In situations like this, it is all the more important to treat official announcements and unconfirmed information separately.