Rotational slide

Definition

A rotational slide is a type of landslide characterized by the movement of soil or rock along a curved surface, typically involving a mass of material that rotates backward as it descends. This phenomenon occurs when the gravitational force acting on the slope exceeds the strength of the materials, leading to failure. Rotational slides are often associated with steep slopes and can be triggered by factors such as heavy rainfall or earthquakes.

5 Must Know Facts For Your Next Test

1. Rotational slides typically occur on slopes with a steep gradient and can result in significant property damage and landscape alteration.
2. The curved failure surface in a rotational slide distinguishes it from other types of slides, such as translational slides, which move along a flat surface.
3. Heavy rainfall or rapid snowmelt can saturate soil, increasing pore water pressure and reducing friction, making slopes more susceptible to rotational slides.
4. Rotational slides often leave behind characteristic features like scarps and depressions on the slope where the material has moved.
5. Mitigation measures for rotational slides include drainage systems to reduce water accumulation and stabilization techniques to reinforce vulnerable slopes.

Review Questions

• What conditions are most likely to lead to a rotational slide occurring on a slope?
  • Rotational slides are most likely to occur on steep slopes where the gravitational force exceeds the strength of the material. Conditions that contribute to this include heavy rainfall, rapid snowmelt, or seismic activity, all of which can saturate the soil and increase pore water pressure. When these factors weaken the soil's cohesion and frictional resistance, it can lead to failure along a curved surface, resulting in a rotational slide.
• Compare and contrast rotational slides with translational slides in terms of their mechanics and characteristics.
  • Rotational slides and translational slides both involve mass wasting but differ significantly in their mechanics. Rotational slides occur along a curved surface, causing the material to rotate backward as it moves down the slope. In contrast, translational slides happen along a flat surface with little rotation, resulting in a more straightforward sliding motion. This difference affects their shapes and potential impacts on the landscape; rotational slides create distinct depressions and scarps while translational slides may cause more uniform displacement.
• Evaluate the impact of human activities on the frequency and severity of rotational slides in hilly regions.
  • Human activities such as deforestation, construction, and road building can significantly increase the frequency and severity of rotational slides in hilly areas. These actions often destabilize slopes by removing vegetation that stabilizes soil, increasing runoff that saturates soil layers, or altering natural drainage patterns. As slopes become more vulnerable due to these disturbances, the likelihood of rotational slides increases, which can lead to serious environmental and economic consequences for communities living in affected regions.

Related terms

mass wasting:

The process by which soil and rock move down a slope under the influence of gravity, encompassing various types of landslides.

landslide: A general term for the downward movement of earth materials, which can occur as rock falls, slides, or flows.

slump: A specific type of rotational slide where a block of soil or rock moves downward along a curved surface, often leaving a distinct scarp.