Huge mistake in Japan's earthquake alert! The 6.9 quake was announced as 9.9

A magnitude‑6.9 earthquake struck near the village of Ozernovski in the south of Russia’s Kamchatka Peninsula on Friday morning. According to a report by The Japan Times, the shaking was also felt in Hakodate, Japan.

After the quake, the Japan Meteorological Agency’s early‑warning system experienced an error. The magnitude was mistakenly announced as 9.9. Although the erroneous alert was retracted a few minutes later, the announcement sparked panic among the public.

If the quake had truly been magnitude 9.9, it would have eclipsed the 1960 Valdivia earthquake in Chile, the largest ever recorded and measured to date at magnitude 9.5.

Which are the world’s largest earthquakes?

According to data from the U.S. Geological Survey (USGS), the strongest earthquakes recorded to date include the following tremors:

Chile – 1960:The 9.5‑magnitude Valdivia earthquake entered the records as the largest measured earthquake. The disaster claimed 1,655 lives, and about 2 million people were left homeless.

Alaska – 1964: In the roughly five‑minute‑long 9.2‑magnitude earthquake, 130 people lost their lives.

Sumatra – 2004:The 9.1‑magnitude earthquake triggered a massive tsunami in the Indian Ocean. The disaster claimed the lives of more than 250,000 people.

Japan – 2011: The 9.1‑magnitude Tohoku earthquake triggered a massive tsunami and led to the Fukushima nuclear disaster.

Kamchatka – 1952The 9.0‑magnitude earthquake produced tsunami waves that reached as far as Hawaii and rose to about 9 meters in some areas.

How would a 9.9‑magnitude earthquake lead to destruction?

The earthquake’s magnitude is closely linked to the size of the ruptured fault and the energy released. As the area of the fault that breaks expands, larger earthquakes can occur.

A 9.9‑magnitude earthquake would release far more energy than the largest tremors recorded to date. Because the magnitude scale is logarithmic, such an earthquake could release roughly 32,000 times more energy than a 6.9‑magnitude quake.

For a quake of this scale to occur, a massive fault stretching thousands of kilometres would have to rupture. In such a scenario, the shaking could last several minutes and cause extremely heavy destruction, especially in areas close to the epicenter.

Large displacements on the sea floor could trigger destructive tsunamis. Permanent uplift or subsidence in coastal areas could also occur.

Could It Even Affect the Earth's Rotation?

Very large earthquakes can alter the mass distribution on Earth, causing extremely small differences in the planet's rotation. These changes could be so minute that they are measurable only in microseconds.

According to the USGS, the earthquake magnitude scale has no fixed upper limit mathematically. However, Earth's physical size and tectonic structure constrain the size of earthquakes that can occur. For instance, an earthquake of magnitude 12 would require a fault larger than the planet itself to rupture.

In the incident in Japan, the 9.9 figure that caused panic did not reflect the true magnitude of the earthquake but rather an error in the early warning system.