The phenomenon measured by the Richter scale is the magnitude of earthquakes. Developed in 1935 by Charles F. Richter, this logarithmic scale quantifies the energy released during seismic events. Each whole number increase on the Richter scale represents a tenfold increase in amplitude of the seismic waves recorded. For example, a magnitude 5 quake has waves ten times larger than a magnitude 4 quake. The Richter scale has been largely replaced by the moment magnitude scale in modern seismology, but it remains well-known to the public for its straightforward representation of earthquake strength.