Which of the following describes the consequences of major geologic events?

• A. Lava flows and ash only.
• B. Earthquakes cause mudslides and landslides.
• C. Volcanic activity can cause lava flows, falling ash, release of gas, tsunamis, and avalanches; earthquakes can cause mudslides, landslides, and falling rocks; mountain building accelerates weathering.
• D. No atmospheric effects.

Answer: (C)

Major geologic events produce a wide range of effects that touch the surface, the atmosphere, and hazards people must manage. Volcanic activity can bring lava flows, falling ash, and the release of gases, and when eruptions interact with bodies of water they can generate tsunamis; volcanic debris can also trigger avalanches of material. Earthquakes bring ground shaking and can cause mudslides, landslides, and rockfalls, and long-term processes like mountain building increase exposure of rocks to weathering, speeding up erosion. Together these points show how geologic activity reshapes landscapes in multiple ways and across different systems.

The other options are too limited or incorrect. Lava flows and ash capture only part of volcanic effects, leaving out gas release, tsunamis, and avalanches. Earthquakes do cause mudslides and landslides but this choice ignores other seismic hazards and volcanic-related impacts. Claiming there are no atmospheric effects overlooks how volcanic ash and gases influence air quality and climate.