A volcano made up of just lava, thick and slow-flowing, creating steep sides is known as which type?

• A. Stratovolcano
• B. Shield volcano
• C. Lava dome
• D. Acidic volcano

Answer: (D)

The shape of a volcano is controlled by how thick the lava is when it erupts. Thick, viscous lava doesn’t flow far; it piles up near the vent and forms a dome with steep sides. This creates a lava dome, a mound built from sticky, silica-rich magma that doesn’t travel far before cooling and solidifying. Shield volcanoes have broad, gently sloping sides from low-viscosity lava that spreads out widely, while stratovolcanoes are built from alternating layers of lava flows and tephra, not a single viscous lava mass. The term “acidic volcano” isn’t a standard way to classify volcano shapes, even though acidic (silica-rich) magma can contribute to dome formation. So the description best fits a lava dome.