Japan retracts mistaken magnitude 9.9 quake alert

JUST IN: Japan retracts a mistaken magnitude 9.9 earthquake alert that triggered emergency warnings on millions of phones, saying a 6.9 quake actually struck near Russia's Kamchatka Peninsula.

Magnitude 9.9. That's the alert millions of phones in Japan screamed out, and it wasn't real.

For context, 9.9 would be the most powerful earthquake ever recorded on this planet, bigger than the 2011 quake that caused the Fukushima disaster. So when that number lit up screens nationwide, people had every reason to be terrified.

The Japan Meteorological Agency has now retracted it, and officials walked the press through what actually happened. A real quake did strike, a magnitude 6.9, but it hit near Russia's Kamchatka Peninsula, well away from Japan. Somewhere between the sensors and the system, 6.9 became 9.9, and emergency warnings went out at full volume.

Japan's alert system is admired worldwide precisely because people trust it instantly and act on it. A false alarm this size chips at that trust, and the agency now has to explain how its machines invented the biggest earthquake in history.

This is Liu Yang, reporting for HIT.