Mercalli scale and Richter scale


Mercalli scale


The intensity of an earthquake, it is determined from reported effects of the tremor on human begins, furniture, buildings, geological structure ...etc.

XII Damage total. Lines of sight and level are distorted. Objects thrown into the air.
XI Bridges destroyed. Rails bent greatly.
X Some well-built wooden structure destroyed; most masonry and frame structures destroyed with foundations. Rails bent.  
IX Damage considerable in specially designed structure. Damage great in substantial buildings. Building shifted off foundations.  
VIII Damage slight in specially designed structure. Fall of chimneys, factory stacks, columns, monuments, walls. Heavy furniture overturned.  
VII Damage slight to moderate in well-built ordinary structures; considerable damage in poorly built or badly designed structures.    
VI Felt by all, many frighten and run outdoors. Some heavy furniture moved.    
V Felt by nearly everyone. Some dishes, windows broken. Unstable objects returned. Pendulum clocks may stop.    
IV Felt indoors by many. Sensation like heavy truck striking building.      
III Felt quite noticeably by person indoors, especially on upper floors of buildings.      
II Felt only by a few persons at rest, especially on upper floors of buildings.      
I Not felt except by a very few.      
                 
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3

4

5

6

7

8

8.9

 
Richter scale

Richter scale


The magnitude of an earthquake is estimated using the amplitudes and periods of earth movement, it is logarithmic and is an indication of the amount of energy released at the focus.