Earthquake magnitudes: what do they mean?
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The following describes the typical effects of earthquakes of various magnitudes near the epicenter.
|
Magnitude? |
Earthquake?Effects?? |
Estimated Number/Year |
|
2.5 or less?? |
Usually not felt, but can be recorded by seismograph? |
900,000?? |
|
2.5 to 5.4?? |
?Often felt, but only causes minor damage |
30,000? |
|
5.5 to 6.0? |
Slight damage to buildings and other structures? |
500? |
|
6.1 to 6.9? |
?May cause a lot of damage in very populated areas |
?100?? |
|
7.0 to 7.9?Major earthquake |
?Serious damage? |
?20?? |
|
8.0 or greater Great earthquake? |
Can totally destroy communities near the epicenter? |
?One every 5 to 10 years |
Earthquake Magnitude Classes Earthquakes are also classified in categories ranging from minor to great, depending on their magnitude.
|
Class |
Magnitude |
|
Great |
8 or more |
|
Major |
7 - 7.9 |
|
Strong |
6 - 6.9 |
|
Moderate |
5 - 5.9 |
|
Light |
4 - 4.9 |
|
Minor |
3 -3.9 |
