Barren Island was formed by a tectonic plate that sank, melted, and rose to the surface. Over years of dried lava and magma build up, it formed a volcano on the somewhat small island. Barren Island is the only active volcano in the Indian Subcontinent. The volcano has a central cone and two lava flows which pour out to the sea and continue to build the island. However, when rain or snow occurs, the sides will slowly crumble and reveal more of the surface area. Barren Island is expect to grow more flat and larger in size.