Earthquakes on an extraordinary scale

The 1960 Valdivia earthquake in Chile, magnitude 9.5, is the largest earthquake in the USGS record since 1900. “Largest” here refers to magnitude, not the number of people affected or the intensity at a particular location.

Five of the largest recorded events

The first five entries in the USGS list are shown below. Dates use UTC, which can differ from the local calendar date. The Alaska earthquake occurred on March 27 locally and March 28 in UTC.

“View region” centers our globe on the historical location. Its earthquake circles show recent activity, not a replay of the historical event.

What does the difference in magnitude mean?

Try comparing M9.5 and M9.0 in the magnitude calculator. Even a half-unit difference represents a substantial change in earthquake size. Enter the values yourself to compare amplitude and estimated energy separately.

Magnitude describes the source; it cannot summarize an event’s full consequences. Depth, distance, ground conditions, buildings, and secondary effects also matter. Read magnitude vs. intensity before interpreting “largest” as “worst everywhere.”

How to explore the list

Open a region and switch on plate boundaries. Compare the geography of Chile, Alaska, Japan, and Kamchatka with the Ring of Fire. Then find Sumatra to put the locations into a wider global context.

This is a selected view of the instrumental record. It is not a complete catalog of ancient earthquakes, and historical magnitude estimates can be revised. The linked USGS list provides references for the individual estimates.