A volcano is formed primarily by the movement of tectonic plates beneath the Earth's surface. When one tectonic plate is forced underneath another in a process called subduction, the subducted plate melts due to the heat and pressure, forming molten rock called magma. This magma is less dense than the surrounding rock and rises toward the surface through openings in the Earth's crust. When magma erupts at the surface, it is called lava. Repeated eruptions cause the lava and volcanic material to build up in layers, eventually forming the cone-shaped mountain we recognize as a volcano. Volcanoes can also form at divergent boundaries where tectonic plates move apart, allowing magma to rise and fill the gap, creating new crust. Additionally, volcanoes can arise over hotspots where magma from deep within the mantle melts through the crust independently of plate boundaries. There are different types of volcanoes, including stratovolcanoes (cone-shaped with explosive eruptions) and shield volcanoes (with gentle slopes and fluid lava flows), depending on the nature of the magma and eruption style. Summarized processes:

• Subduction zones where one plate goes under another, melting and magma rising.
• Rift zones or divergent boundaries where plates move apart, allowing magma to surface.
• Hotspots where magma rises through the crust independently of plate boundaries.

This volcanic activity creates volcanic mountains over time as lava cools and solidifies in layers.