Which term describes slow moving molten rock that is damaging to the land?

• A. Lava Flow
• B. Ash Fall
• C. Mudflows
• D. Pyroclastic Flow

Answer: (A)

Lava flow is the term for molten rock that erupts and moves downslope, typically at a slow to moderate pace. This molten rock can burn, bury, and obliterate anything in its path and then harden into new rock as it cools, reshaping the landscape. The other options describe hazards that aren’t molten rock moving slowly: ash fall is fine volcanic ash settling from the atmosphere; mudflows (lahars) are fast-moving mixtures of water and volcanic debris; pyroclastic flows are extremely hot, fast currents of gas and volcanic fragments. Because the question stresses slow movement of molten rock damaging the land, lava flow fits best.