Describe the formation of convergent volcanoes.

Cracks or weaknesses in the convergent plate boundaries allow magma to come up. Pressure from the gases from the oceanic crust when it was subducted, pushes magma from the mantle into the crust. Gases build up to make a volcano erupt. After several eruptions when the lava cools and solidifies, it creates a mountain or cone-like shape, forming a composite volcano. It releases andesitic lava which has a high silica content, meaning ts more viscous, so the lava won't travel far.