What is the term for when rocks on the side of a steep slope collapse?

The term for when rocks on the side of a steep slope collapse is "landslide." This phenomenon occurs when gravity overcomes the strength of the material, causing a sudden movement of earth or rock down a slope. Landslides can involve a variety of different materials, including soil, rock, and vegetation, and they often occur as a result of factors such as heavy rainfall, earthquakes, volcanic activity, or human activities that destabilize the slope.

Landslides can vary widely in size and scale, and they can pose significant risks to people, infrastructure, and the environment. In contrast, an earthquake refers specifically to the shaking of the ground caused by tectonic movements, a flood involves an overflow of water onto normally dry land, and a rockfall describes the specific event where individual rocks or rock debris fall from a steep surface, which is a more specific type of landslide. Therefore, the term "landslide" encompasses the broader category of slope failure, making it the correct answer in this context.