Human activities, including deforestation and construction, can have a profound impact on slope stability, leading to increased risks of landslides and soil erosion.

A prominent case study illustrating these effects is the 2014 Oso landslide in Washington State, United States. This catastrophic event resulted in the tragic loss of 43 lives and was primarily linked to human actions that destabilized the slope. Extensive logging in the area had removed vital vegetation that played a crucial role in binding the soil and absorbing excess water. As a result, the slope became significantly more vulnerable to landslides, especially during periods of intense rainfall.

In addition to deforestation, the construction of homes at the base of the slope further exacerbated the risk of landslides. The excavation of soil and rock for building purposes can destabilize slopes, heightening the likelihood of landslides. In the Oso incident, not only did the construction activities compromise slope stability, but they also placed residents directly in the path of potential landslides.

Moreover, the establishment of a fish hatchery at the summit of the slope was identified as another contributing factor. The hatchery required substantial amounts of water, which was drawn from a nearby river. This increased the moisture content in the soil, making it heavier and more susceptible to movement.

The Oso landslide serves as a poignant reminder of the potential consequences of human activities on slope stability. It underscores the importance of meticulous planning and management of activities in landslide-prone areas, particularly concerning deforestation and construction. Key measures include conducting comprehensive geotechnical assessments prior to construction, implementing effective land use policies, and promoting sustainable practices such as reforestation.