Which Scale Rates Earthquake Damage At A Particular Location

The Modified Mercalli Intensity Scale is the most commonly used scale for rating earthquake damage at a particular location. This scale was originally developed in 1884 by Italian vulcanologist Giuseppe Mercalli and was later modified by American seismologist Harry Wood and Frank Neumann. The scale ranges from I (not felt) to XII (total damage) with each level of intensity describing the effects of the earthquake on people structures and the landscape.

The Modified Mercalli Scale is generally used to measure the damage caused by an earthquake at a particular location rather than the strength of the earthquake itself. This is because the intensity of an earthquake can vary depending on factors such as the size and depth of the earthquake the type of rocks involved and the distance from the epicenter.

The Modified Mercalli Scale is divided into twelve levels of intensity from I to XII. Each level of intensity is associated with a certain amount of damage and effects on people structures and the landscape.

Level I: Not felt except by a very few under specially favorable conditions.

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

Level III: Felt quite noticeably by people indoors especially on upper floors of buildings. Many people do not recognize it as an earthquake. Standing automobiles may rock slightly. Vibrations similar to the passing of a truck. Duration estimated.

Level IV: Felt by nearly everyone; many awakened. Some dishes windows and doors broken. Unstable objects overturned. Pendulum clocks may stop.

Level V: Felt by all many frightened. Some heavy furniture moved; a few instances of fallen plaster. Damage slight.

Level VI: Felt by all many frightened and some panicky. Significant damage in well-constructed buildings; damage considerable in poorly constructed buildings. Some masonry and frame structures damaged; a few collapsed. Fall of chimneys factory stacks columns monuments and walls. Heavy furniture overturned.

Level VII: 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. Some underground pipelines burst. Heavy objects thrown into the air.

Level VIII: Damage severe in all structures. Well-designed structures thrown violently off their foundations. Damage great in substantial buildings with complete collapse. Buildings and bridges destroyed. Large landslides.

Level IX: Damage severe in all structures. Ground badly cracked. Underground pipelines completely disrupted. In the area ground leveling fissuring and shaking damages most structures. Rails bent.

Level X: Some structures remain standing but are severely damaged. All others are destroyed. Ground level is greatly lowered in places. Underground pipelines completely disrupted.

Level XI: Total damage. Objects are thrown into the air. The ground is greatly raised or lowered in places. Large cracks appear in the ground. Underground pipelines are completely disrupted.

Level XII: Damage is total. The area is levelled by the earthquake. Objects are thrown high into the air. The ground is liquefied.

What is the highest level on the Modified Mercalli Intensity Scale?

X (Extreme)

Leave a Comment