Phones screamed at 12:40 in the afternoon. Across northern and eastern Japan, from the snowy ports of Hokkaido to the packed commuter trains of Tokyo, emergency alerts lit up with a warning that would make anyone’s blood run cold: a magnitude 9.9 earthquake was about to strike. Eight minutes later, it was all over. The warning was wrong.
The Japan Meteorological Agency, the country’s trusted early warning system, on Friday issued one of the most dramatic false alarms in its history, before quietly retracting it and bowing in apology. What actually happened was real enough, just far less terrifying: a magnitude 6.9 earthquake beneath the sea near Russia’s Kamchatka Peninsula, more than a thousand kilometres from Tokyo, had shaken the ground and rattled the algorithms.
A real quake, an unreal number
The actual earthquake struck at 12:38 pm Japan time on Friday, centred near the Kamchatka Peninsula at a depth of about 140 to 160 kilometres. The European Mediterranean Seismological Centre first reported it at magnitude 7.0 before settling on 6.9. Because of its depth, the shaking barely registered in Japan. In Hakodate, on the southern tip of Hokkaido, instruments recorded an intensity of 1 on Japan’s seismic scale, the kind of tremor most people would never notice.
But inside the meteorological agency’s computers, something went badly wrong. The early warning system detected the seismic waves at 12:38:10 and began the rapid calculation that underpins Japan’s world-leading alert network. An intermediate estimate hit magnitude 7.3 within seconds. Then, at 12:39:23, the system’s assessment jumped to a staggering 9.9, and misplaced the epicentre near the Kuril Islands, between Hokkaido and Kamchatka. At 12:40:02, the first emergency bulletin went out, predicting seismic intensity 7, the maximum on Japan’s scale, across a vast area from Hokkaido to central Japan.
Eight minutes of chaos
For eight minutes, the country braced for catastrophe. Mobile phones blared the familiar alert tone simultaneously across the warned regions. Television broadcasts interrupted regular programming. On the Tokaido Shinkansen, the busiest bullet train line in the world, services were automatically suspended as a safety precaution. Commuters froze. Shopkeepers stepped into the streets. Parents tried to reach their children.
Then, at 12:48, the agency issued a notice in the same emergency bulletin format, this time cancelling the earlier alert. The magnitude was revised down to 6.9. The epicentre was moved to Kamchatka. The strongest shaking Japan would actually feel had already come and gone, unnoticed by most.
A 9.9 magnitude earthquake would have been almost beyond comprehension. The strongest earthquake ever recorded instrumentally, the 1960 Valdivia quake in Chile, measured 9.5. A 9.9 would have released energy dozens of times greater than even that. Japan, which lived through the magnitude 9.1 Tohoku earthquake and tsunami of 2011, knows better than any country what such numbers mean. That collective memory is exactly why the false alarm hit so hard.
An apology and a probe
Hours later, the meteorological agency held a press conference and apologised for the erroneous report. Officials explained that the system had initially fixed the epicentre at the Kuril Islands and overestimated the magnitude as 9.9, and said an investigation into the cause of the miscalculation was underway. At the press conference, Ayataka Ebita, head of the agency’s Earthquake and Tsunami Monitoring Division, was asked whether a cyberattack might have been responsible. The answer, relayed from the agency’s systems staff, was no.
It is a highly unusual case for the agency to issue an emergency earthquake bulletin and then fully cancel it. Japan’s early warning system is considered the most advanced in the world, issuing alerts seconds after detection and saving lives since its launch. But the system is only as good as its automatic first estimates, and on Friday, the automated processing misjudged both where the quake was and how big it was.
Why Kamchatka keeps making headlines
Kamchatka lies on the Pacific Ring of Fire, one of the most seismically active zones on the planet. The peninsula regularly experiences earthquakes above magnitude 7. In July 2025, a magnitude 8.8 quake near Kamchatka triggered tsunami warnings across parts of the Pacific, and the region has recorded dozens of earthquakes in the past month alone, the 6.9 on Friday being the largest of that period.
For now, there is no tsunami threat from Friday’s quake, according to the US National Tsunami Warning Center, and no casualties or significant damage have been reported. What remains is a shaken public trust and a pointed question for the agency: how does a 6.9 become a 9.9? The investigation will need to answer that convincingly, because in a country where the next big one is always a matter of when, not if, the warning system must never cry wolf again.
Key facts at a glance
- Real earthquake: Magnitude 6.9 near Russia’s Kamchatka Peninsula, depth around 140-160 km, at 12:38 pm JST on Friday.
- False warning: Japan’s meteorological agency issued a magnitude 9.9 alert at 12:40 pm, withdrawn eight minutes later at 12:48 pm.
- Impact: Shinkansen services suspended briefly; only intensity 1 shaking recorded in Hakodate, Hokkaido.
- No tsunami threat was issued, and no casualties or major damage have been reported.
- Response: The agency apologised and launched an investigation; cyberattack ruled out.
Frequently asked questions
Did a magnitude 9.9 earthquake actually hit Japan?
No. The real earthquake measured magnitude 6.9 and struck near Russia’s Kamchatka Peninsula. The 9.9 figure was an error by Japan’s automated early warning system, corrected within eight minutes.
Was there any tsunami risk?
No. The US National Tsunami Warning Center said there was no tsunami threat, and Japan’s agency did not issue any tsunami advisory for this event.
Why did the system get the magnitude so wrong?
The agency says its automated processing initially placed the epicentre near the Kuril Islands instead of Kamchatka and overestimated the magnitude. The exact cause is under investigation, but officials have ruled out a cyberattack.
What does magnitude 9.9 mean compared to past quakes?
The largest earthquake ever recorded, the 1960 Valdivia quake in Chile, was magnitude 9.5. A 9.9 would have been far larger than even that, and far larger than the 9.1 Tohoku quake of 2011.
Is Kamchatka prone to big earthquakes?
Yes. The peninsula sits on the Pacific Ring of Fire. In July 2025, a magnitude 8.8 quake there triggered Pacific-wide tsunami warnings.
Japan’s early warning system remains one of the world’s best. Friday’s false alarm is a reminder that even the finest technology can fail, and that trust, once rattled, takes time to rebuild.
