Seismic Intensity : Three (III) - Weak

Three (III) : Felt indoors by several, motion usually rapid vibration. Felt quite noticeably by people indoors, especially on the upper floors of buildings. Many do not recognize it as an earthquake. Standing automobiles may rock slightly. Vibration similar to the passing of a truck. Duration can be estimated. Indoor objects (including chandeliers) may shake.

Perceived Shaking


Potential Damage


Peak Ground Motion Acceleration

1.0 to 1.4 (%g)

Peak Ground Motion Velocity

0.5 - 1.1 (cm/sec)

Video Example

Intensity Three (III)

Reference: Modified Mercalli Intensity Scale (Adapted from Sieberg's Mercalli—Cancani scale, modified and condensed)