UPSC 2004: Consider the following geological phenomena: 1. Development of a fault 2. Movement along a fault 3. Impact produced by a volcanic eruption 4. Folding of rocks Which of the above cause earthquakes?

Earthquakes are triggered by any sudden release of energy in the lithosphere. (1) The formation or development of a new fault involves brittle rupture that releases seismic energy; (2) slip or movement along an existing fault is the most common cause of earthquakes; (3) volcanic explosions or the rapid movement of magma also create seismic shocks. Folding of rocks (4) is a slow, ductile deformation and does not generate sudden seismic waves. Hence only 1, 2 and 3 are causes of earthquakes. ([uttarpradesh.pscnotes.com](https://uttarpradesh.pscnotes.com/uppcs-prelims/consider-the-following-geological-phenomena-development-of-a-fault/?utm_source=openai))