Rockslide
Topic: Geomorphic Processes: Weathering, Mass Movement, Erosion and Soil Formation · NCERT: Class 11, Ch 5 "Geomorphic Processes"
Meaning
A rockslide is the sliding of large rock masses down a surface of weakness. That surface may be a bedding plane (the boundary between rock layers), a joint (crack) or a fault. Rockslides often happen as planar failures (sliding along a flat surface) where rock layers dip steeply in the same direction as the slope. They are very fast and destructive. Unlike a rock fall, they can involve rock to a considerable depth, so very large volumes move at once.
Example
In the Himalayas, layers of sedimentary rock often dip steeply towards valleys. When roads or rivers cut the base of such a slope, whole slabs of rock slide down the bedding planes. This happens often in Uttarakhand districts such as Rudraprayag.
Don't confuse with
- Rock fall: blocks fall freely and keep away from the slope, and only surface layers are affected. A rockslide moves along a plane and goes deep.
- Slump: the mass rotates backwards on a curved surface. A rockslide moves on a fairly flat plane without rotating.
Related concepts
- Mass movement
- Activating causes of mass movement
- Soil creep
- Solifluction
- Mudflow
- Debris avalanche
- Slump
- Rock fall