Which of the following are examples of major geologic events?

• A. Mountain building, earthquakes, volcanic eruptions, rising groundwater, undercutting, etc.
• B. Mountain building and earthquakes only.
• C. Earthquakes, volcanoes, tsunamis.
• D. Solar flares cause geologic events.

Answer: (A)

Major geologic events are large-scale processes that reshape Earth's crust and landscapes. This includes both deep-seated tectonic activities and surface changes that significantly alter rocks and landforms. Mountain building reflects the long-term growth of crust through plate interactions. Earthquakes are the rapid release of stored stress in rocks, rearranging or breaking structures. Volcanic eruptions alter the surface by expelling magma and building new landforms. At the surface, processes like rising groundwater can change rock stability and drive landscape evolution, while undercutting removes support at the base of slopes and can trigger collapses or new landforms. Together, these examples cover the breadth of major geologic change, from deep Earth processes to surface modifications. The other options are too limited or reference phenomena that aren’t geologic events themselves, such as solar flares.