Which volcano type is a mound formed by the extrusion of viscous lava near the vent?

Which volcano type is a mound formed by the extrusion of viscous lava near the vent?

• A. Stratovolcanoes
• B. Shield volcanoes
• C. Volcanic domes
• D. Calderas

Answer: (C)

When lava is very viscous, it doesn’t flow far from the vent. Instead, it piles up around the vent, forming a rounded, steep-sided mound. This creates a volcanic dome, typically built from high-silica lava like rhyolite or andesite that extrudes slowly and blocks from spreading out. In contrast, a stratovolcano grows from alternating eruptions that build up layered lava and ash into a tall, composite cone; a shield volcano forms from low-viscosity lava that travels far and spreads into a broad, gentle slope; and a caldera is a large volcanic depression caused by the collapse of a magma chamber after a major eruption. So the mound-shaped feature produced by extruding viscous lava near the vent is a volcanic dome.

When lava is very viscous, it doesn’t flow far from the vent. Instead, it piles up around the vent, forming a rounded, steep-sided mound. This creates a volcanic dome, typically built from high-silica lava like rhyolite or andesite that extrudes slowly and blocks from spreading out. In contrast, a stratovolcano grows from alternating eruptions that build up layered lava and ash into a tall, composite cone; a shield volcano forms from low-viscosity lava that travels far and spreads into a broad, gentle slope; and a caldera is a large volcanic depression caused by the collapse of a magma chamber after a major eruption. So the mound-shaped feature produced by extruding viscous lava near the vent is a volcanic dome.