A logarithmic scale of 1 to 10 formerly used to express the magnitude of an earthquake on the basis of the size of seismograph oscillations WordNet 3.0 & Open English WordNet

The Richter scale, also called the Richter magnitude scale, Richter's magnitude scale, and the Gutenberg–Richter scale, is a measure of the strength of earthquakes, developed by Charles Francis Richter and presented in his landmark 1935 paper, where he called it the "magnitude scale". Wikipedia

The energy of an earthquake, superseded by Moment scale Wikipedia Disambiguation

A scale measuring the strength of earthquakes, created by Charles Francis Richter Wikipedia Disambiguation

Seismic magnitude scale Wikidata

A logarithmic scale used to express the energy released by an earthquake, each increase of 1 representing a 32-fold increase in energy. Wiktionary

Logarithmic scale. Wiktionary (translation)