The biggest earthquakes in recorded history
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Since systematic measurement began, five earthquakes have stood apart from all others. They share two things: all happened where one plate is forced beneath another — and all triggered devastating tsunamis.
The five strongest measured quakes
- 1. Valdivia, Chile, 1960 — M9.5. The strongest quake ever measured. The rupture was over 1,000 km long, and the tsunami reached both Hawaii and Japan.
- 2. Alaska, USA, 1964 — M9.2. The "Good Friday earthquake" lasted over four minutes and lifted parts of the coast by several metres.
- 3. Sumatra, Indonesia, 2004 — ca. M9.1–9.3. The Indian Ocean tsunami killed around 230,000 people in 14 countries — one of the worst natural disasters of modern times.
- 4. Tōhoku, Japan, 2011 — M9.0–9.1. The tsunami flooded long stretches of coast and triggered the Fukushima accident.
- 5. Kamchatka, Russia, 1952 — M9.0. Sent a tsunami across the Pacific to Hawaii.
How much energy are we talking about?
Because the magnitude scale is logarithmic, the leap from "big" to "biggest" is enormous: the Valdivia quake released on the order of gigatonnes of TNT — more energy than years of global electricity consumption, released in minutes.
Why does an M10 never happen?
A quake's maximum size is limited by how long a continuous fault rupture can be. Even Earth's longest subduction zones "only" allow roughly M9.5 — Valdivia probably came close to the physical limit. An M10 would require a rupture many thousands of kilometres long, and no such continuous fault exists.
Could it happen again?
Yes — megaquakes strike the same subduction zones at intervals of centuries, which is why the plate boundaries are monitored more closely than ever. On EarthquakeIndex's live map you can watch exactly those zones at work every single day.