Richter Scale
By Ismael Gba
The Richter Scale is the best known scale for measuring the magnitude of earthquakes. The magnitude value is proportional to the strongest wave during an earthquake. A recording of 7, for example, indicates a disturbance with ground motion 10 times as large as a recording of 6. The energy released by an earthquake increases for every unit increase in the Richter scale. The table below gives the frequency of earthquakes and the effects of the earthquakes based on this scale. The biggest earthquake ever recorded was in Chile which hit the Richter scale 9.8.
Richter scale no. |
No. of earthquakes per year |
Typical effects of this magnitude |
< 3.4 |
800 000 |
Detected only by seismometers |
3.5 – 4.2 |
30 000 |
Just about noticeable indoors |
4.3 – 4.8 |
4 800 |
Most people notice them, windows rattle. |
4.9 – 5.4 |
1400 |
Everyone notices them, dishes may break, open doors swing. |
5.5 – 6.1 |
500 |
Slight damage to buildings, plaster cracks, bricks fall. |
6.2 6.9 |
100 |
Much damage to buildings: chimneys fall, houses move on foundations. |
7.0 – 7.3 |
15 |
Serious damage: bridges twist, walls fracture, buildings may collapse. |
7.4 – 7.9 |
4 |
Great damage, most buildings collapse. |
> 8.0 |
One every 5 to 10 years |
Total damage, surface waves seen, objects thrown in the air. |
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