Describe about Rotational slides.

Slides refer to landslides, the movement of land mass is called a landslide. The mass of soil gets detaches from the parent mass due to the different reasons due to the rupture at certain points. This rupture follows a certain geometry which becomes the basis for categorizing different types of slides. These are majorly distributed into two types:

1. Translational slide:

These are those slides in which the landmass that slides moves along a rough planar surface with a bit of rotation or backward tilting. This type of landslide moves the soil mass in a single unit.  

2. Rotational slide:

In rotational slide the surface rupture is curved concavely upward and the slide movement is roughly rotational about an axis parallel to the ground surface and transverse across the surface rupture.

In more practical words, in translational slide the surface over which slide occurs is approximately parallel to the slope surface while, in rotational slide the surface is curved, the upper part moves downward and the lower part moves outward. Rotational slide is also called as slump.