State any two causes of earthquakes.

The two main causes of earthquakes are:

1. Volcanic eruptions — Volcanic earthquakes are caused by gas explosions. They occur either simultaneously with eruption or more commonly in the period preceding an eruption. For example - Krakatoa volcano caused a severe earthquake that its impact was experienced at Cape Horn (12,800 km away).
2. Plate Tectonics — Tectonic plates move and slide over each other and their edges produce faults along the line of weakness. This movement of plates causes earthquakes. For example - In 2001, a severe earthquake occurred in Bhuj, Gujarat in India because of the lowering of the Indian plate below the Asiatic plate.