10.0 megaquake

 A 10.0 megaquake refers to a hypothetical earthquake with a magnitude of 10.0 on the moment magnitude scale (Mw).

Has a 10.0 earthquake ever happened?

No.

The largest earthquake ever recorded was the 1960 Valdivia earthquake in Chile, which measured 9.5 Mw.

How powerful would a 10.0 be?

The earthquake scale is logarithmic, meaning:

• Each whole number increase = 10× stronger ground motion
• Each whole number increase = ~32× more energy released

So a 10.0 quake would release:

• About 32 times more energy than a 9.0
• About ~3 times more energy than the 9.5 Chile quake

That’s an almost unimaginable amount of energy.

Is a 10.0 even possible?

Most scientists believe a 10.0 earthquake is extremely unlikely on Earth because:

• Fault lines are not long or wide enough to generate that much energy.
• The planet’s tectonic structure likely limits earthquakes to around 9.5–9.7 maximum.

Some subduction zones (like parts of the Pacific Ring of Fire) could theoretically approach it, but current models suggest Earth probably cannot produce a true 10.0.

What would happen if it did?

If a 10.0 occurred near a populated coastal region:

• Massive ground shaking over thousands of kilometers
• Widespread structural collapse
• Huge tsunamis (possibly larger than those from the 2011 Tōhoku earthquake and tsunami in Japan)
• Global economic and infrastructure disruption

It would likely be the most destructive natural disaster in recorded human history.

If you’d like, I can compare:

• 9.0 vs 9.5 vs 10.0 visually
• What cities would be most at risk
• Or how the energy compares to nuclear weapons