Name at least two processes that change Earth's surface quickly.

Two processes that change Earth's surface quickly are volcanic eruptions and landslides.

To understand why these processes cause rapid changes to Earth's surface, let's break them down:

1. Volcanic eruptions: Volcanoes are openings in the Earth's crust through which molten rock, volcanic ash, and gases are released. When a volcano erupts, it can have several immediate effects:
a. Lava flows: Molten rock (lava) is expelled from the volcano and can flow downhill, covering large areas and altering the landscape. As the lava cools and solidifies, it forms a new layer of igneous rock.
b. Pyroclastic flows: During an explosive eruption, a mixture of hot gases, ash, and volcanic debris races down the volcano's slopes at high speeds, demolishing everything in their path. These pyroclastic flows can transport large boulders and reshape the terrain.
c. Ashfall: Ash particles can be ejected into the atmosphere during an eruption and fall back to the ground as fine dust, covering vast regions. Ashfall can bury existing topography and alter soil fertility.

2. Landslides: Landslides are the sudden downslope movement of a mass of rocks, debris, or soil. They can be triggered by various factors, including:
a. Steep slopes: In areas with steep slopes, gravitational forces can exceed the strength of the materials holding the slope together, causing a landslide.
b. Heavy rainfall: Prolonged or intense rainfall saturates the soil, reducing its stability. This excess water acts as a lubricant, encouraging landslides to occur more easily.
c. Earthquakes: Seismic activity can shake loose soil and rocks, initiating landslides in vulnerable locations.

Both volcanic eruptions and landslides can occur suddenly and have significant impacts on Earth's surface, reshaping landscapes and altering the natural environment.