Correct Option
The correct option is 1, 2, 3 and 4.
Explanation
Earthquakes are classified into various types based on their mode of origin and the specific causative factors involved. While the majority are caused by natural geological processes, some are induced by human activities.
Statement-wise Analysis
- Statement 1 is Correct: Tectonic earthquakes are the most common type of earthquakes. They are generated due to the sliding of rocks along a fault plane. The sudden release of energy during this slippage generates seismic waves that cause ground shaking.
- Statement 2 is Correct: Collapse earthquakes are typically associated with areas of intense mining activity. In these regions, the roofs of underground mines may collapse, causing minor tremors on the surface.
- Statement 3 is Correct: Explosion earthquakes are induced by human activities. Ground shaking occurs due to the detonation of chemical or nuclear devices. These tremors are generally localized to the area of the explosion.
- Statement 4 is Correct: Volcanic earthquakes are a specific class of earthquakes confined to areas of active volcanoes. They are caused by the movement of magma, volcanic gas pressure, or explosive eruptions.
Key Takeaway: Earthquakes are categorized by their source: Tectonic (fault movement), Volcanic (magma activity), Collapse (mining roof failure), and Explosion (weapon testing/detonations).