| Scale |
Description |
| Magnitude |
Mercalli |
| 0-2.9 |
I |
Detected only by sensitive instruments |
| II |
Felt only by a few persons at rest, especially on upper floors of buildings; delicately suspended objects may swing |
| III |
Felt noticeably indoors, especially on upper floors of buildings, but not always recognized as earthquake; standing autos may rock slightly; vibrations like a passing truck |
| 2.9-4.1 |
IV |
During the day, felt indoors by many, outdoors by few; at night, some awakened; dishes, windows, doors disturbed; walls make creaking sound; sensation like heavy truck hitting building; standing autos rock noticeably |
| V |
Felt by most people; some breakage of dishes, windows, and plaster; unstable objects overturned; disturbance of trees, poles, and other tall objects |
| 4.1-5.4 |
VI |
Felt by all, many frightened and run outdoors; some heavy furniture may move; falling plaster and chimneys, damage slight |
| VII |
Everyone runs outdoors; damage to buildings varies depending on quality of construction; noticed by people driving autos |
| 5.4-7.3 |
VIII |
Panel walls thrown out of frames; walls, monuments, chimneys fall; sand and mud ejected; drivers of autos disturbed |
| IX |
Buildings shifted off foundations, frame structures thrown out of plumb; ground cracked; underground pipes broken |
| X |
Most masonry and frame structures destroyed*; ground badly cracked, rails bent, landslides; sand and mud shift; water splashes over river banks |
| 7.3 + |
XI |
Few structures remain standing; bridges destroyed; broad fissures in ground, pipes broken, landslides, rails bent |
| XII |
Damage total; waves seen on ground surface, lines of sight and level distorted, objects thrown up into the air |