Richter scale

American  

noun

1. a scale, ranging from 1 to 10, for indicating the intensity of an earthquake.

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Richter scale British  

/ ˈrɪxtə /

noun

1. a scale for expressing the magnitude of an earthquake in terms of the logarithm of the amplitude of the ground wave; values range from 0 to over 9 Compare Mercalli scale See also magnitude

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Richter scale Scientific  

/ rĭk′tər /

1. A logarithmic scale used to rate the strength or total energy of earthquakes. The scale has no upper limit but usually ranges from 1 to 9. Because it is logarithmic, an earthquake rated as 5 is ten times as powerful as one rated as 4. An earthquake with a magnitude of 1 is detectable only by seismographs; one with a magnitude of 7 is a major earthquake. The Richter scale is named after the American seismologist Charles Francis Richter (1900–1985).

2. See Note at earthquake

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Richter scale Cultural  

1. A scale used to rate the intensity of earthquakes. The scale is open-ended, with each succeeding level representing ten times as much energy as the last. A serious earthquake might rate six to eight, and very destructive quakes rate higher.

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Discover More

No quake greater than nine has ever been recorded.

Etymology

Origin of Richter scale

1935–40; after Charles F. Richter (1900–85), U.S. seismologist

Compare meaning

How does richter-scale compare to similar and commonly confused words? Explore the most common comparisons:

• Mercalli scale vs. Richter scale

Example Sentences

Magnitudes on the Richter scale are measured logarithmically, with each whole number increase representing ten times more in measured amplitude.

From Barron's • May 11, 2026

Typically, one earthquake per year reaches a magnitude of 8.0 or higher, while around 15 others fall within the magnitude 7 range on the Richter scale, which measures the amount of energy released.

From Science Daily • Jan. 6, 2026

"Her confusion level was just off the Richter scale."

From BBC • Dec. 18, 2025

Earlier this year, a government panel estimated that there is an 80% chance of a magnitude 8 to 9 megaquake on the Richter scale occurring along Japan’s Nankai Trough in the next 30 years.

From Los Angeles Times • Jul. 8, 2025

It was 7.6 on the Richter scale and was felt as far away as Kabul and Delhi.

From "Malala: The Girl Who Stood Up for Education and Changed the World" by Malala Yousafzai