Landslides are primarily caused by the force of gravity acting on weathered materials. When the stability of a slope is compromised—often due to factors such as heavy rainfall, earthquakes, or human activity—the gravitational force can overcome the friction holding the soil and rock in place. This leads to the sudden movement of these materials down the slope, resulting in a landslide.
Additionally, the weathering process plays a crucial role in preparing the materials for this movement. Chemical weathering can weaken the bonds within rocks and soil, while physical weathering can create loose debris that is easily mobilized. Together, these processes can significantly increase the likelihood of a landslide occurring when gravity exerts its force on the weakened slope.