Search results
Results From The WOW.Com Content Network
Dobbingstone Burn, Scotland—This photo illustrates two different types of erosion affecting the same place. Valley erosion is occurring due to the flow of the stream, and the boulders and stones (and much of the soil) that are lying on the edges are glacial till that was left behind as ice age glaciers flowed over the terrain.
There are two primary mechanisms of stream bank erosion: fluvial erosion and mass failure. Fluvial erosion is the direct removal of soil particles by flowing water. The rate of fluvial erosion is determined both by the force of the flowing water (e.g. faster flow equals more force) and the resistance of the bank material to erosion (e.g. clay is generally more resistant to erosion than sand).
While erosion is a natural process, human activities have increased by 10–40 times the rate at which soil erosion is occurring globally. [7] At agriculture sites in the Appalachian Mountains , intensive farming practices have caused erosion at up to 100 times the natural rate of erosion in the region. [ 8 ]
River erosion in the UK. River bank failure can be caused when the gravitational forces acting on a bank exceed the forces which hold the sediment together. Failure depends on sediment type, layering, and moisture content. [1] All river banks experience erosion, but failure is dependent on the location and the rate at which erosion is occurring ...
Understanding the principle of isostasy is a key element to understanding the interactions and feedbacks shared between erosion and tectonics. The principle of isostasy states that when free to move vertically, lithosphere floats at an appropriate level in the asthenosphere so that the pressure at a depth of compensation in the asthenosphere well below the base of the lithosphere is the same. [3]
temporal variation in land use and land cover (LULC): it includes the human abandonment of farming areas, e.g. due to the economic and social transformations which occurred in Europe after the Second World War. Land degradation and extreme rainfall can increase the frequency of erosion and landslide phenomena. [8]
Mudflows often start as slides, becoming flows as water is entrained along the flow path; such events are often called mud failures. [ 5 ] Other types of mudflows include lahars (involving fine-grained pyroclastic deposits on the flanks of volcanoes) and jökulhlaups (outbursts from under glaciers or icecaps).
Human impact on the environment. From top left, clockwise: satellite image of Southeast Asian haze; IAEA experts investigate the Fukushima disaster; a seabird during an oil spill; depiction of deforestation of Brazil's Atlantic forest by Portuguese settlers, c. 1820 –25; acid mine drainage in the Rio Tinto; industrial fishing in 1997, a practice that has led to overfishing.