Here's why:
* Gravity's Pull: Gravity constantly pulls everything towards the Earth's center. This force is what causes loose soil, rocks, and other materials to move downslope.
* Slope Angle: The steeper the slope, the stronger the pull of gravity. This makes it more likely for material to slide or fall.
* Water's Role: Water plays a significant role by:
* Lubricating: Water can make the ground slippery, reducing friction and allowing material to move more easily.
* Adding weight: Water absorbed into soil increases its weight, making it more prone to sliding.
* Eroding: Rainwater can erode the ground, making it less stable.
In summary: While other factors like vegetation, earthquakes, and human activity can contribute, gravity is the primary force driving the erosion and deposition associated with landslides, mudslides, and rockfalls.
