The main differences between these two types of volcano are based on how they look and where they are found. Composite cone volcanoes (also known as stratovolcanoes) are mainly found at subduction zones (destructive plate boundaries). On the other hand, shield volcanoes are found at constructive plate boundaries and hotspots. Composite cone volcanoes are made of hardened layers of ash and lava, and have a steep, cone-like shape. Its lava has high levels of silica and a high viscosity which makes eruptions highly destructive. Key examples are Mount Pinatubo in the Philippines and Mount St. Helens in the USA. Meanwhile, shield volcanoes have very fluid lava (low viscosity) that can travel very far during eruptions, and this accumulates as broad, gently-sloped layers that look like a 'shield'. One key example of a shield volcano is Mauna Loa in Hawaii where eruptions have little silica and are therefore non-explosive.