Which volcano type is formed by layering lava and ash?

Which volcano type is formed by layering lava and ash?

• A. Composite volcanoes
• B. Cinder cone volcano
• C. Shield volcano
• D. Lava dome

Answer: (A)

Composite volcanoes, also known as stratovolcanoes, are built up by repeated eruptions that lay down alternating layers of hardened lava flows and volcanic ash and pumice (tephra). When magma erupts, the lava may flow a short distance and solidify, while other eruptions eject ash clouds and tephra that settle and harden into distinct layers. Over many cycles, these alternating layers accumulate into a tall, steep-sided cone. This layering pattern is what sets them apart from other volcano types. The other forms behave differently: cinder cones primarily pile loose tephra around the vent, creating smaller, conical mounds with little lava flow material; shield volcanoes form from low-viscosity lava that spreads out into broad, gentle slopes; lava domes arise from viscous lava that piles up near the vent rather than creating long, layered builds.

Composite volcanoes, also known as stratovolcanoes, are built up by repeated eruptions that lay down alternating layers of hardened lava flows and volcanic ash and pumice (tephra). When magma erupts, the lava may flow a short distance and solidify, while other eruptions eject ash clouds and tephra that settle and harden into distinct layers. Over many cycles, these alternating layers accumulate into a tall, steep-sided cone. This layering pattern is what sets them apart from other volcano types.

The other forms behave differently: cinder cones primarily pile loose tephra around the vent, creating smaller, conical mounds with little lava flow material; shield volcanoes form from low-viscosity lava that spreads out into broad, gentle slopes; lava domes arise from viscous lava that piles up near the vent rather than creating long, layered builds.