The vast majority of volcanic activity occurs where tectonic plates collide, called convergent boundaries, or spread, called divergent boundaries. However, there is a special class of volcanoes that form within plates. These inter-plate volcanoes are known as hotspot volcanoes.Hotspot volcanoes that form under continental plates are called super volcanoes, representing the most powerful and violent volcanoes on Earth.owever, there is a special class of volcanoes that form within plates. These inter-plate volcanoes are known as hotspot volcanoes. Hotspot volcanoes that form under continental plates are called super volcanoes, representing the most powerful and violent volcanoes on Earth.