Mercalli Scale
A measure of the intensity of an earthquake. This is a subjective value that varies depending on where the earthquake is observed. The ratings vary from I (felt only under especially favourable circumstances) to XII (total destruction).
| I | Generally not felt. |
| II | Felt by a few people, suspended objects may swing. |
| III | Felt by a few people, similar vibration levels to a passing truck. |
| IV | Felt by most people indoors, but few outdoors. Windows, doors and dishes rattle. |
| V | Nearly everybody will feel it. People woken and small objects may topple. |
| VI | Felt by everyone, heavy furniture moves, books fall from shelves, bushes and trees visibly shake. |
| VII | Difficult to stand. Some damage to poorly constructed buildings, tiles and loose bricks fall. Small landslides on slopes. Water becomes turbid. |
| VIII | Difficult to steer a car. Damage to good buildings, chimneys. Tree branches break and steep slopes crack. |
| IX | Extensive building damage, underground pipes break. |
| X | Most walls destroyed, large landslides, water thrown from rivers and lakes onto the banks. |
| XI | Most masonry buildings destroyed, railroad tracks bent and most underground pipework destroyed. |
| XII | More or less total destruction, objects thrown into the air. |
See also: Richter Scale, Seismic, Seismograph.
Subjects: Noise & Vibration