Largest earthquakes worldwide 1900-2024, by magnitude

The 1960 Great Chilean earthquake was the largest measured on the Richter scale, with a magnitude of 9.5. The second most powerful earthquake since 1900 took place in Alaska in 1964. An earthquake with a magnitude of 9.0 and higher is defined as causing near or total destruction, including severe damage or collapse to all buildings.

Earthquakes and the Richter scale – additional information 

An earthquake occurs when two tectonic plates under the Earth’s surface slip past one another, resulting in the sudden release of energy in the Earth's crust. The sudden violent tremors can cause destruction to infrastructure, human injury, and even death. 
There are a number of ways to measure the magnitude of an earthquake. One of the first and most widely-used methods is the Richter scale. The Richter magnitude scale was developed by the seismologist, Charles F. Richter, in 1935. On the Richter Scale, magnitude is expressed in whole numbers and decimal fractions, but is based on a logarithmic scale. For example, a magnitude 5.3 might be computed for a moderate earthquake, and a strong earthquake might be rated as magnitude 6.3. 

Deadliest earthquakes

Despite its strong magnitude, the earthquake in Chile in 1960 does not appear on the list of the 10 deadliest earthquakes in the world since 1900. The 1976 earthquake in Tangshan, China, caused the highest death toll, while the earthquake that hit Haiti in 2010 caused the second highest death toll.