Earthquakes Can Be classified into different categories on the basis of region where it occurs and the geological make-up of that region as :
(i) Tectonic earthquake: most commonly it occurs when rocks in the earth's crust break due to geological forces created by movement of tectonic plates.
(ii) Volcanic earthquake: it occurs in conjunction with volcanic activity.
(iii) Collapse earthquake: these are the small earthquakes which occur in underground mines and caverns.
(iv) Explosion earthquake: these mainly occur due to the explosion of nuclear and chemical devices.