Scientific explanation for volcanoes

Answer 1

According to the theory of plate tectonics, volcanoes happen in two different places on the earth's crust. 1) Hotspots: areas with permanent, intense convection currents in the liquid mantle that break through the crust. Example of this is the Hawaiian island chain. 2) Subduction zones: areas where two tectonic plates collide, and one plate moves beneath the other. This creates huge deep cracks called rifts, and when the subducted plate melts, an area of pressurized magma is formed that pushes upwards through the continent and creates explosive volcanoes. These chains of volcanoes can be seen in the US Pacific northwest, as well as inland of the Peru trench in South America.