Most of the earthquakes result from the “Motion of Plates”. When two or more plates collide with each other, it causes earthquakes. How hard and long the earthquake will be completely based on the strength of collision.
The human being is so smart here that they build a whole “Earthquake Magnitude Scale”, see below table.
|Magnitude||Class||Earthquake Effects||Estimated Number|
|2.5 or less||Minor||Usually not felt, but can be recorded by a seismograph.||900000|
|2.5 to 5.4||Light||Often felt, but only causes minor damage.||30000|
|5.5 to 6.0||Moderate||Slight damage to buildings and other structures.||500|
|6.1 to 6.9||Strong||May cause a lot of damage in very populated areas.||100|
|7.0 to 7.9||Major||Major earthquake. Serious damage.||20|
|8.0 or more||Great||Great earthquake. Can totally destroy communities near the epicenter.||One every 5 to 10 years|