Modified Mercalli Intensity Scale of Earthquake Effect

Features

Level

not felt except by a very few under especially favorable conditions

I

felt only by a few persons at risk, especially on the upper floors of buildings; delicately suspended objects may swing

II

felt quite noticeably by persons indoors, especially on the upper floors of buildings; many people do not recognize it as an earthquake; standing cars may rock slightly; vibration similar to the passing of a truck; duration can be estimated

III

felt indoors by many; felt outdoors by few; at night some awakened; dishes, windows and doors disturbed; walls may make cracking sound; sensation like heavy truck striking the building; standing cars rock noticeably

IV

felt by nearly everyone; many awakened; some dishes and windows broken; unstable objects overturn; pendulum clocks may stop

V

felt by all with many frightened; some heavy furniture moved; damage slight; ceiling plaster may fall

VI

damage negligible in buildings of good design and construction; slight to moderate in well-built ordinary structures; considerable damage in poorly built or badly designed buildings; some chimneys broken

VII

damage slight in specially designed structures; considerable damage in ordinary substantial buildings with partial collapse; damage great in poorly built structures; chimneys, factory stacks, columns, monuments and walls fall; heavy furniture overturned

VIII

damage considerable in specially designed structures; well-designed frame structures thrown out of plump; damage great in substantial buildings with partial collapse; buildings shifted off foundations

IX

some well-built wooden structures destroyed; most masonry and frame structures destroyed with foundations; rails bent

X

few if any masonry buildings remain standing; bridges destroyed; rails bent greatly

XI

total destruction; lines of sight and level are distorted; objects thrown into the air

XII