نتایج جستجو برای: alluvial fans
تعداد نتایج: 7388 فیلتر نتایج به سال:
introduction this research addresses the automatic extraction of alluvial fans using four methods of segmentation from satellite data. this segmentation method divides images into partitions. it is typically used to recognize objects or other relevant purposes in digital images (fu, 2013:3260). alluvial fans have always been a landform that attracts human because they are suitable areas for liv...
despite of suitable geological and climatic conditions for forming and evolution of alluvial fans and importance of this landform as soil and water resources in arid regions, there are limited studies about this landform in iran. in the present study, evolution and pedogenic development of geomorphic surfaces of an alluvial fan in eastern isfahan were studied by using remote sensing, field and ...
River deltas and alluvial fans have channelization and deposition dynamics that are not entirely understood, but which dictate the evolution of landscapes of great social, economic, and ecologic value. Our lack of a process-based understanding of fan dynamics hampers our ability to construct accurate prediction and hazard models, leaving these regions vulnerable. Here we describe the growth of ...
The surfaces of alluvial fans and river deltas (collectively fans) are often dissected by a small number of channels radiating from the fan apex. On long timescales, channels migrate via avulsion, the process of channel bed deposition and abandonment that often results in catastrophic flooding and loss of life on densely populated fans. We present results of an experimental fan that creates rea...
Water and debris fl ows exiting confi ned valleys have a tendency to deposit sediment on steep fans. On alluvial fans where water transport of gravel predominates, channel slopes tend to decrease downfan from ~0.10–0.04 to ~0.01 across wide ranges of climate and tectonism. Some have argued that this pattern refl ects grain-size fi ning downfan such that higher threshold slopes are required just...
Collapsing gullies are among the most severe soil erosion problems in the tropical and subtropical areas of southern China. However, few studies have examined the relationship of soil particle size distribution (PSD) changes with land-use patterns in the alluvial fans of collapsing gullies. Recently, the fractal method has been applied to estimate soil structure and has proven to be an effectiv...
Detecting Landforms Using Quantitative Radar Roughness Characterization and Spectral Mixing Analysis
In Geomorphology the landforms delineation and delimitation are based on traditional techniques which is usually achieved by two different approaches: semantic and geometric. The semantic approach involves interpreting aerial photographs as well as using field knowledge to map the possible landforms extent. The geometric approach involves inferring the probability of extension on related proper...
Megafans (100-600 km radius) are very large alluvial fans that cover significant areas on most continents, the surprising finding of recent global surveys. The number of such fans and patterns of sedimentation on them provides new mesoscale architectures that can now be applied on continental fluvial depositional systems, and therefore on . Megafan-scale reconstructions underground as yet have ...
Combined effects of brush encroachment and channel entrenchment in the Southwestern United States threaten ecological, hydrological, and agricultural functions of ephemeral streams and associated alluvial surfaces. Restoration is difficult because entrenchment is widespread, and highly variable flow magnitudes defy standardized structural approaches. Methods developed by the Zuni Indians during...
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