Question: how are volcanos formed

anon answered on 16 Oct 2020:

Volcanoes are the surface expression of a deep process in the mantle.

Our planet is covered by plates, or rafts of crust. These move very slowly and create volcanoes in seveeral ways.

When an edge slides under another edge the fiction can melt the rock and a blister forms, this is the volcano (like South America)

When edges move apart, they leave a gap and the volcanoes can be conical or very long (like Iceland).

Sometimes, like a pot boiling, the magma can form hotspots and a volcano, usually conical, can form.