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?

The correct answer is Option 4 (1, 2, 3 and 4). Earthquakes are vibrations caused by the sudden release of energy in the Earth's crust, and all four phenomena listed are recognized triggers.

• Faulting (1 & 2): The development of a fault involves the fracturing of rocks under tectonic stress, while movement along a fault (elastic rebound) is the most common cause of major earthquakes.
• Volcanic Eruption (3): Explosive volcanic activity or the movement of magma underground creates volcanic earthquakes due to intense pressure changes and structural collapses.
• Folding (4): While folding is a plastic deformation, extreme compressional stress leading to folding often reaches a breaking point, causing crustal shortening and associated seismic shocks.

Since seismic waves can be generated by any sudden displacement of rock masses or internal pressure shifts, all four geological processes contribute to seismic activity, making Option 4 the most comprehensive and accurate choice.