Landslides. A landslide is the rapid mass movement of soil, mud and/or rocks downhill due to the pull of gravity. Landslides are very common and occur in a variety of forms. Land may topple off in a big chunk, or slip down in bits.Landslide may be composed of mud or may contain rocks and other debris.oil is therefore heaviest and most susceptible to the effects of gravity, when saturated. When large areas of soil become saturated on steep slopes, the pull of gravity causes the top layers of the soil to slide downhill, therefore resulting in a landslide.