Dome volcano is characterized by

Dome volcano is characterized by

• A. A broad shield-like shape with gentle slopes
• B. A volcano with steep sides that is formed by lava flows
• C. A crater lake surrounded by ash deposits
• D. A small cone built from volcanic ash

Answer: (B)

The main idea here is how magma viscosity shapes a volcano. When magma is highly viscous, it doesn’t flow far from the vent. Instead, it oozes out slowly and piles up around the vent, building a dome with steep sides. That’s exactly what a dome volcano is: a steep-sided mound formed by lava that doesn’t spread out into wide lava flows. So, a volcano with steep sides formed by lava flows best captures this idea. The other options describe different volcanic shapes: a broad shield volcano forms from low-viscosity lava that travels long distances and creates gentle slopes; a crater lake with ash deposits describes crater features, not the overall form; a small cone built from volcanic ash refers to a cinder cone, which is made from tephra rather than viscous lava forming a dome.

The main idea here is how magma viscosity shapes a volcano. When magma is highly viscous, it doesn’t flow far from the vent. Instead, it oozes out slowly and piles up around the vent, building a dome with steep sides. That’s exactly what a dome volcano is: a steep-sided mound formed by lava that doesn’t spread out into wide lava flows.

So, a volcano with steep sides formed by lava flows best captures this idea. The other options describe different volcanic shapes: a broad shield volcano forms from low-viscosity lava that travels long distances and creates gentle slopes; a crater lake with ash deposits describes crater features, not the overall form; a small cone built from volcanic ash refers to a cinder cone, which is made from tephra rather than viscous lava forming a dome.