Who developed the Richter scale?

Charles F. Richter developed the Richter scale, formally called the local-magnitude scale, in collaboration with Beno Gutenberg. Their work was published in 1935 at the California Institute of Technology and created a practical way to compare earthquake sizes using instrumental records.

Richter’s system is logarithmic: a one-unit increase represents a tenfold increase in recorded wave amplitude and roughly 31.6 times more energy release. It was designed for shallow earthquakes in Southern California, using readings from standardized Wood–Anderson seismographs and corrections for distance from the epicenter.

The scale became famous under Richter’s name, but Beno Gutenberg made important contributions, especially in extending the method and developing related magnitude scales. That is why “Gutenberg–Richter” sometimes appears in technical references. Henry Reid is associated with elastic rebound theory, and John Milne helped pioneer global seismology and seismograph networks, but neither developed the Richter scale.

For large modern earthquakes, agencies generally report moment magnitude rather than the original Richter scale because the latter saturates and becomes unreliable for very powerful events. News reports still often use “Richter” as a general shorthand.