Why are high volcanoes such as the Cascades found on the continents and in a row parallel to the continental margin?

High volcanoes like those in the Cascades are typically found at convergent plate boundaries, where an oceanic plate subducts beneath a continental plate. This subduction process causes magma to form as the oceanic plate melts, leading to volcanic activity. The alignment of these volcanoes in a row parallel to the continental margin reflects the direction of the tectonic plates' movement and the specific areas where magma can escape to the surface. Thus, their location is a direct result of the geological processes associated with plate tectonics.