Stratovolcanoes, also known as composite volcanoes, are tall, conical volcanoes characterized by their layered structure of hardened lava, tephra, and ash. They typically form at convergent plate boundaries, where an oceanic plate subducts beneath a continental plate. This process leads to explosive eruptions due to the high viscosity of the magma, which traps gas. These volcanoes can produce a variety of eruption styles, ranging from gentle lava flows to violent explosions. Famous examples of stratovolcanoes include Mount St. Helens in the United States and Mount Fuji in Japan. Their eruptions can significantly impact surrounding environments and human populations.