Like other types of volcanoes, stratovolcanoes form around vents from which molten rock, or magma, reaches the Earth’s surface as lava. They’re most common along the planet’s great subduction zones, where a tectonic plate plunges beneath another, generating the rock melt necessary to produce volcanic activity.

What are stratovolcanoes composite formed from?

Key Takeaways: Composite Volcano Composite volcanoes, also called stratovolcanoes, are cone-shaped volcanoes built from many layers of lava, pumice, ash, and tephra. Because they are built of layers of viscous material, rather than fluid lava, composite volcanoes tend to form tall peaks rather than rounded cones.

What kind of rocks creates the stratovolcanoes?

Stratovolcanoes are composed of volcanic rock types that vary from basalt to rhyolite, but their composition is generally andesite. They may erupt many thousands of times over life spans of millions of years. A typical eruption begins with ash explosions and ends with extrusion of thick, viscous lava flows.