Earthquakes

The Mercalli and Richter Scales

There are two major scales in which earthquakes are measured. These two scales are the Mercalli Scale and the Richter scale. The Mercalli scale was created by Giuseppe Mercalli at the turn of the 20th century.  His scale measures the intensity of shaking with numbers from I to XII.   The Richter Scale was named after the American seismologist Charles Francis Richter. This scale measures the motion of the land surface 60 miles from the epicenter of the earthquake.

Mercalli Scale

Richter Scale

I

 Hardly felt

0-4.3

 People at rest in upper floors will notice shaking.
The shaking is mostly felt in doors and hanging objects will swing.

II

 Felt only by a few people at rest or on top floors of buildings.    

III

 Can be felt by people indoors, especially on top floors of buildings. Many people do not recognize it as an earthquake.    

IV

 Can be felt by many people indoors, but only a few outdoors. Might waken some people at night. Dishes, windows, and doors shake.    

V

 Felt by nearly everyone. Many people wake up. Some dishes and windows broken. Some objects will be knocked.

4.3-4.8

 Sleeping people will  wake. Dishes, doors and trees shake and sway.

VI

 Felt by all.

4.8-6.2

People will have trouble walking steadily.
Windows break; plaster, bricks, and tiles will fall to the ground.

VII

 A lot of damage in poorly built or badly designed buildings.    

VIII

 A lot of damage in poorly built structures and heavy furniture can be turned over.    

IX

 A lot of damage in buildings with good design and build, some will even collapse. Buildings can be shifted off their foundation.    

X

 Many objects destroyed and buildings collapse.    

XI

 Few structures remain standing and bridges are destroyed.

6.2-7.3

General panic among people.  Damage to foundations causing buildings to be destroyed.
Water thrown out of river.

XII

 Total destruction.

7.3-8.9

 Total destruction.

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