Intensity
How strongly shaking is felt and how much damage occurs at a specific location.
Intensity measures the effects of an earthquake at a particular place, not the energy at the source. It is rated on the Modified Mercalli scale from I (not felt) to XII (total destruction).
Unlike magnitude, which is one number per quake, intensity varies from spot to spot. It depends on distance from the source, the depth of the rupture, and the type of ground underfoot. Soft sediment amplifies shaking, which is why two neighborhoods the same distance from a quake can experience very different damage.
Related terms
Magnitude
A number describing the energy an earthquake released at its source, on a logarithmic scale.
Epicenter
The point on the surface directly above where an earthquake's rupture began.
Hypocenter Depth
How far below the surface an earthquake's rupture began, which shapes how hard the surface shakes.