Hazards and Disasters


The Mercalli Scale of Earthquake Intensity

The Mercalli scale measures the power of an earthquake as felt by humans and structures. It was developed in 1902 by Italian geologist Giuseppe Mercalli. The Mercalli scale is written in roman numerals and it ranges from I (barely felt) to XII (catastrophic). The Mercalli scale can be mapped surrounding an epicenter and will vary based on the geology of an area.

I Barely felt
II Felt by a few people, some suspended objects may swing
III Slightly felt indoors as though a large truck were passing
IV Felt indoors by many people, most suspended objects swing, windows and dishes rattle, standing autos rock
V Felt by almost everyone, sleeping people are awakened, dishes and windows break
VI Felt by everyone, some are frightened and run outside, some chimneys break, some furniture moves, causes slight damage
VII Considerable damage in poorly built structures, felt by people driving, most are frightened and run outside
VIII Slight damage to well-built structures, poorly built structures are heavily damaged, walls, chimneys, monuments fall
IX Underground pipes break, foundations of buildings are damaged and buildings shift off foundations, considerable damage to well-built structures
X Few structures survive, most foundations destroyed, water moved out of banks of rivers and lakes, avalanches and rockslides, railroads are bent
XI Few structures remain standing, total panic, large cracks in the ground
XII Total destruction, objects thrown into the air, the land appears to be liquid and is visibly rolling like waves


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