Which term matches the definition: 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 that fits this definition. It describes molten rock that erupts and then moves downslope as a viscous liquid across the land. Because the rock is molten, it can burn, fuse, or bury whatever it encounters, causing lasting damage to air, soil, vegetation, roads, and structures as it advances slowly over time.

Ash fall, by contrast, consists of fine volcanic ash particles ejected into the air and settling to the ground rather than molten rock moving along the surface. Mudflows (lahars) are mixtures of water, rock, and ash that rush down valleys—not molten rock. Pyroclastic flows are rapidly moving crowds of hot gas and volcanic fragments, extremely fast and dangerous but not slow-moving molten rock.