What factor commonly triggers mass movements?

Mass movements, which include landslides, rockfalls, and mudflows, are influenced by various factors that can destabilize soil and rock on slopes. Earthquakes can generate powerful shaking that disrupts the stability of the ground, leading to a sudden mass movement. Similarly, when surface materials become saturated with water, the added weight and reduced friction can promote sliding and flow of materials. The removal of vegetation lessens root support for soil, making it more susceptible to erosion and mass movement.

Given that each of these factors—earthquakes, water saturation, and deforestation—can independently trigger mass movements, it follows that all of them collectively contribute to the occurrence of such events. Therefore, recognizing their individual and combined effects is crucial for understanding the dynamics of mass movements in the context of Earth science. This comprehensive view allows us to appreciate the multifaceted nature of the triggers behind mass movements.