How do earthquake magnitudes differ from earthquake intensity?

Magnitude values such as moment magnitude describe the size of the earthquake itself, using seismic data from the fault rupture. Intensity, on the other hand, is based on observed shaking, damage, and people's experiences at a particular place. The same quake can feel much stronger near the epicenter than far away, so intensity maps vary across a region. The older Richter scale was used widely for smaller local earthquakes, but modern seismology relies mainly on moment magnitude. This distinction helps the public understand why a moderate quake can still cause severe damage in one area and little harm in another.