Mass Wasting Essay Samples

Mass wasting is defined as the downward movement of loose rock, soil, mud and regolith under the force of gravity. The nature of flow is determined by the cohesive and frictional forces between the particles and agents like water play an important role in transporting the material to lower elevations. This article focuses on Creep, Earthflow, Mudflow, Rock falls, Rockslides and Underwater landslides.
Creep- Creep or Soil Creep is a very slow and long term process of downslope movement of soil. Shear forces, over time, are only slightly greater than shear strengths. Creep is triggered by gravity and the rate of downward movement depends on the angle of slope. Creep is not visible to the naked eye and the rate of movement is usually less than a centimeter per year. The two significant factors contributing to the creep are water in the soil and daily cycles of freezing and thawing.
Earthflow- Earthflow can be slow or rapid and involves downslope movement of earth as a viscous fluid. Earthflows usually occur on hillsides that have a thick cover of soil in which finer grains are predominant, often after heavy rains have saturated the soil. The earthflow can happen slowly or rapidly, the pace of which is decided by the water content and the type of material or soil. Earthflow is triggered owing to a variety of reasons which include heavy rains, human activities such as unscientific digging for mud, cutting across mountains etc.
Mudflow- A mudflow is a flowing mixture of soil and water, usually moving down a channel. Mudflow will be viscous and can be visualized as a stream with the consistency of a thick milk shake. Mudflows are usually triggered by heavy rainfalls and are strong enough to cause large scale destruction.
Rock falls- A rock fall can be defined as the downward motion or free fall and bouncing, rolling and sliding of detached blocks of bedrocks. Rock falls occur both in natural and man-made environments. Geology and climate which includes discontinuities, frost wedging, water, stress levels etc. are the natural determining factors for a rock fall, whereas the man-made reasons include cutting rock for road/dam constructions, mining, deforestation etc.
Rockslide- A rockslide can be defined as the rapid sliding of mass of bedrock when pieces of rock break due to a major fracture in the rock or a bedding plane. Post the trigger, the rock slabs break into rubble and can be caused by undercutting at the base of the slope from erosion or construction. Water is an aiding factor for rockslide and exceptionally heavy rains can cause the water to seep into the inner layers of rock thereby lifting the sandstone from the wet surface of shale. Other aiding factors for a rockslide include earthquakes, plant-root wedging, expanding ice etc.
Underwater Landslides- An underwater landslide, as the name indicates is the landslide happening under the water. Huge landslides happen underwater as well where a vast area of mountainous regions fails to hold them up resulting in landslides. Underwater landslides have the capability to trigger a tsunami, but fortunately large landslides do not happen frequently. Underwater landslides can be triggered due to various factors which include weak geological layers, earthquakes, groundwater seepage, volcanic activity, gas pressure build up etc.