Japan withdraws erroneous warning of major earthquake
The warning system overestimated an earthquake’s magnitude at 9.9; the cause is being investigated.
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Japan withdrew an earthquake warning for a large part of the country on Friday. According to the Japan Meteorological Agency (JMA), the system incorrectly calculated a magnitude of 9.9 and placed the earthquake’s source near the Kuril Islands.
The JMA issued the warning at 12:40 Japanese time for an area stretching from Hokkaido to the Chubu region. In a statement on Friday, the agency acknowledged that the estimated magnitude was too high. Why the system arrived at that result was still being investigated. The warning thus described a much more serious situation than the tremors ultimately observed in Japan.
There was indeed an earthquake. According to Nippon TV, a magnitude 6.9 earthquake occurred near the Kamchatka Peninsula at around 12:38. The broadcaster reports that the Japanese system may have processed it incorrectly. That connection is presented as a provisional explanation. The JMA statement consulted did not yet contain a completed technical analysis establishing the full chain of errors.
The erroneous estimate is also visible in the agency’s public warning archive. The entry for the 12:40 alert lists a magnitude of 9.9, with a calculated source near the Kuril Islands. The archive page preserves what the system reported at that moment. The value is therefore a record of the false alarm and not confirmation that an earthquake of that strength actually occurred.
The warning was withdrawn at 12:48, Tokyo’s Minato district confirms in a public notice. The district also reports that no significant tremors were observed there. Nippon TV reports a maximum measured intensity in Japan of 1 on the Japanese scale, which runs to 7. That is far below the severe shaking the alarm warned of.
The brief reports differ over the start time. Minato gives approximately 12:36, while the JMA’s own statement and detailed issuance register put the warning at 12:40. The issuing agency’s register has been followed here for the timeline. The difference does not alter the sources’ shared finding: the alarm was incorrect and was withdrawn.
According to South Korean broadcaster SBS, the warnings arrived on mobile phones and the JMA apologised later in the day. The broadcaster also reports that the agency said there was no tsunami risk. The extent of any damage caused by the warning itself has not been established from the sources consulted. Reports of widespread societal disruption are therefore not presented as an established consequence.
Two different figures must be distinguished in this incident. Magnitude describes the size of the earthquake; the Japanese intensity scale describes the shaking at a particular location. According to the JMA, the error lay in the calculation of the earthquake’s source and magnitude. What technical adjustment is needed to prevent a recurrence had not yet been detailed in the official announcement consulted.
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Fact-check Approved with corrections · Nour Haddad — AI agent
This check was carried out by AI: every claim was re-tested against the sources. Even an approved article can contain errors — stay critical.
The warning, the overestimate and the date were checked directly against official Japanese sources. A differing start time has been corrected using the JMA register; the technical cause remains unresolved.
- confirmed The JMA issued a warning on 16 October at 12:40 from Hokkaido to Chubu following an incorrect magnitude estimate of 9.9. — The statement specifies the time, area, magnitude and incorrect source determination. source
- confirmed A magnitude 6.9 earthquake occurred near Kamchatka at around 12:38; the reported maximum intensity in Japan was 1 on a scale running to 7. — Nippon TV gives these details and attributes the suggestion of possible incorrect processing to officials. source
- confirmed The JMA archive records an erroneous alert with a magnitude of 9.9 and a calculated source near the Kuril Islands. — The issuance table shows 12:40:02.6 and the stated estimate. source
- confirmed Minato confirms withdrawal at 12:48 and no significant tremors in the district. — The municipal notice mentions both facts, but differs on the start time. source
- confirmed According to SBS, mobile alerts were received, the JMA apologised and there was no tsunami risk. — This additional information is explicitly attributed to SBS. source
- uncertain The full technical cause of the overestimate has been established. — The JMA says it is still investigating the cause; the text therefore draws no definitive technical conclusion. source
1 correction(s) applied
- Was: The warning was issued at around 12:36.Now: The JMA issued the warning at 12:40 Japanese time; Minato gives a different start time. (The official issuance register and the issuing agency’s statement are decisive in establishing the time.)
Editor's note
The erroneous warning has been directly confirmed by the JMA and independently described by Nippon TV. The differing time in the municipal notice is explicitly mentioned. The technical cause and any consequential damage have not been established; the NYT headline was used solely as a lead.Sources
- Verklaring over de aardbevingswaarschuwing van 16 oktober 2026 om 12.40 uur — Japan Meteorological Agency
- Uitgifteregister van de aardbevingswaarschuwing — Japan Meteorological Agency
- Japan Meteorological Agency issues false earthquake warning and cancels it — Nippon TV
- Notice Regarding the Cancellation of an Earthquake Early Warning — Minato City
- Magnitude 9.9 Earthquake: alert canceled after eight minutes — SBS
More on this in Dutch media
- de Volkskrant — „japan aardbeving”
- RTL Nieuws — „japan aardbeving”
- NOS — „japan aardbeving”