Modified Mercalli Intensity Scale

Intensity	Shaking	Description
I	Instrumental	Not felt except by a very few under especially favorable conditions.
II	Feeble	Felt only by a few persons at rest, especially on upper floors of buildings. Delicately suspended objects may swing.
III	Slight	Felt quite noticeably by persons indoors, especially on the upper floors of buildings. Many do not recognize it as an earthquake. Standing motor cars may rock slightly. Vibration similar to the passing of a truck. Duration estimated.
IV	Moderate	Felt indoors by many, outdoors by few during the day. At night, some awakened. Dishes, windows, doors disturbed; walls make cracking sound. Sensation like heavy truck striking building. Standing motor cars rocked noticeably. Dishes and windows rattle alarmingly.
V	Rather Strong	Felt by nearly everyone; many awakened. Some dishes and windows broken. Unstable objects overturned. Clocks may stop
VI	Strong	Felt by all; many frightened and run outdoors, walk unsteadily. Windows, dishes, glassware broken; books off shelves; some heavy furniture moved or overturned; a few instances of fallen plaster. Damage slight.
VII	Very Strong	Difficult to stand; furniture broken; damage negligible in building of good design and construction; slight to moderate in well-built ordinary structures; considerable damage in poorly built or badly designed structures; some chimneys broken. Noticed by persons driving motor cars.
VIII	Destructive	Damage slight in specially designed structures; considerable in ordinary substantial buildings with partial collapse. Damage great in poorly built structures. Fall of chimneys, factory stacks, columns, monuments, walls. Heavy furniture moved.
IX	Ruinous	General panic; damage considerable in specially designed structures, well-designed frame structures thrown out of plumb. Damage great in substantial buildings, with partial collapse. Buildings shifted off foundations.
X	Disastrous	Some well built wooden structures destroyed; most masonry and frame structures destroyed with foundation. Rails bent.
XI	Very Disastrous	Few, if any masonry structures remain standing. Bridges destroyed. Rails bent greatly.
XII	Catastrophic	Total damage - Almost everything is destroyed. Lines of sight and level distorted. Objects are thrown into the air. The ground moves in waves or ripples. Large amounts of rock may move.

I

Instrumental

Not felt except by a very few under especially favorable conditions.

Instrumental MMI Scale

II

Feeble

Felt only by a few persons at rest, especially on upper floors of buildings. Delicately suspended objects may swing.

Feeble MMI Scale

III

Slight

Felt quite noticeably by persons indoors, especially on the upper floors of buildings. Many do not recognize it as an earthquake. Standing motor cars may rock slightly. Vibration similar to the passing of a truck. Duration estimated.

Slight MMI Scale

IV

Moderate

Felt indoors by many, outdoors by few during the day. At night, some awakened. Dishes, windows, doors disturbed; walls make cracking sound. Sensation like heavy truck striking building. Standing motor cars rocked noticeably. Dishes and windows rattle alarmingly.

Moderate MMI Scale

V

Rather Strong

Felt by nearly everyone; many awakened. Some dishes and windows broken. Unstable objects overturned. Clocks may stop

Rather Strong MMI Scale

VI

Strong

Felt by all; many frightened and run outdoors, walk unsteadily. Windows, dishes, glassware broken; books off shelves; some heavy furniture moved or overturned; a few instances of fallen plaster. Damage slight.

Strong MMI Scale

VII

Very Strong

Difficult to stand; furniture broken; damage negligible in building of good design and construction; slight to moderate in well-built ordinary structures; considerable damage in poorly built or badly designed structures; some chimneys broken. Noticed by persons driving motor cars.

Very Strong MMI Scale

VIII

Destructive

Damage slight in specially designed structures; considerable in ordinary substantial buildings with partial collapse. Damage great in poorly built structures. Fall of chimneys, factory stacks, columns, monuments, walls. Heavy furniture moved.

Destructive MMI Scale

IX

Ruinous

General panic; damage considerable in specially designed structures, well-designed frame structures thrown out of plumb. Damage great in substantial buildings, with partial collapse. Buildings shifted off foundations.

Ruinous MMI Scale

X

Disastrous

Some well built wooden structures destroyed; most masonry and frame structures destroyed with foundation. Rails bent.

Disastrous MMI Scale

XI

Very Disastrous

Few, if any masonry structures remain standing. Bridges destroyed. Rails bent greatly.

Very Disastrous MMI Scale

XII

Catastrophic

Total damage - Almost everything is destroyed. Lines of sight and level distorted. Objects are thrown into the air. The ground moves in waves or ripples. Large amounts of rock may move.

Catastrophic MMI Scale

National Center for Seismology

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