What does earthquake magnitude measure?

Earthquake magnitude measures the energy released during an earthquake. This measurement is crucial because it quantifies the strength of the seismic event, allowing for a comparison between different earthquakes. Magnitude scales, such as the Richter scale or moment magnitude scale, provide a numerical value to this energy release, which can help in assessing the potential damage and impact of the earthquake on structures and populations.

Depth and size of the epicenter refer to different aspects of an earthquake's characteristics, while the frequency of aftershocks pertains to the seismic activity that follows the initial quake, but these do not relate to the magnitude itself. Understanding magnitude is key for seismologists and emergency responders in providing appropriate responses and preparedness measures following seismic events.