What causes a landslide?
A landslide happens when rocks and sediment loosen and roll down a slope (a slanted surface) quickly. One of the things that can cause a landslide is simply when the area is worn down by the weather. Water can cause another kind of weathering called chemical weathering. It is called chemical weathering because water can dissolve rocks and change their chemistry. Earthquakes can also make the rocks and soil unstable. They can come apart and lead to a landslide.
Wildfires burn roots of plants and trees that hold the soil together. Then, gravity takes over to move the soil and start a landslide. Volcanoes can also start a landslide. Landslides after a volcanic eruption are extremely hot, high-speed and dangerous. As you can see, gravity plays a major role in landslides. Even though it is not the trigger for a landslide, without the force of gravity the rocks and soil wouldn't move down the slope.