The Largest Earthquakes Ever Recorded

The top 20 since 1900

This is the U.S. Geological Survey’s ranking of the largest earthquakes with reliable instrumental magnitudes. All values are moment magnitude (M_w). Where the list shows the same magnitude for several earthquakes, the ranking between them is not meaningful — the uncertainty on a great-earthquake magnitude is around ±0.1–0.2.

They are all the same kind of earthquake

Every earthquake in the list is a subduction megathrust: the shallow, gently dipping fault where one tectonic plate slides beneath another. Only that setting offers a fault surface large enough — hundreds of kilometres long and wide — to store the energy of a magnitude 9. Transform faults like the San Andreas top out around magnitude 8 because they are narrower; mid-ocean ridges rarely exceed magnitude 6.

The list is also dominated by a handful of regions: Chile, Alaska and the Aleutians, Kamchatka and the Kurils, Sumatra, and Japan. These are the fastest-converging, longest, and best-locked subduction zones on Earth.

The 1960 Chile earthquake

The magnitude 9.5 earthquake of 22 May 1960 ruptured roughly 1,000 km of the boundary between the Nazca and South American plates. It remains the largest earthquake ever instrumentally recorded and released more seismic energy than every other earthquake of the 1960s put together. Its tsunami crossed the Pacific and killed people in Hawaii, Japan and the Philippines, up to 22 hours after the earthquake.

It is on the interactive map in the 1960 view, a large shallow (red) circle off the coast of central Chile, surrounded by its aftershocks.

Largest is not the same as deadliest

Death tolls depend on where an earthquake strikes, how deep it is, how buildings are constructed, and whether it generates a tsunami — not simply on magnitude. Several of the deadliest earthquakes in history were far smaller than the ones above:

• The deadliest known earthquake struck Shaanxi, China, in 1556, killing an estimated 830,000 people who largely lived in cave dwellings cut into soft loess cliffs.
• The 2010 Haiti earthquake was only magnitude 7.0, but it was shallow and directly beneath a densely populated area with vulnerable buildings; estimates of the death toll range widely, into the hundreds of thousands.
• The 2004 Sumatra earthquake (M9.1) killed about 228,000 people — almost all by tsunami, many of them thousands of kilometres from the epicentre (U.S. Geological Survey).