Dr Mitra Saberi, Dr Amir Karam, Parviz Zeaiean, Ali Ahmadabadi,
Volume 0, Issue 0 (3-1921)
Abstract
many geomorphic landforms have fractal structures and their formation and transformation can be explained by mathematical relations. The purpose of this study is to identify and analyze the fractal behavior of landforms of macro geomorphologic regions of Iran,as well as studying and analyzing topographic and landform characteristics based on fractal relationships, and also, analyzing the characteristics of dominant geomorphologic processes based on the theory of fractals. In this study, the contour lines of different landforms of Iran (according to the territorial types) including mountains,hills, plateaus, Plain Domains, Fan Breakout, fan alluvial, for pixel sizes of 30,90,200 m, were drawn and their fractal dimension was estimated by using the box-counting method. The morphometric characteristics of the landforms and their fractal dimensions with indexes (max, mean and standard deviation) related to the five variables (height, gradient, profile curvature and planar curvature of the metric) were analyzed by Arc GIS software at each layer.After investigating their correlation with the fractal dimension, the regression analysis was performed binary and the relationship between the fractal dimension,topography, landforms and processes was analyzed. The fractal dimension has the highest correlation coefficient with the gradient and the standard deviation indices, and the lowest coefficient with the profile curvature and the mean index Moreover, for larger pixel sizes, the correlation coefficient decreases between the indices and the fractal dimension.This research can provide a ground for further research on fractal geometry in geography, geomorphology, geology, environment and other Earth sciences.
Alireza Jafarzadeh Estalkhkouhi, Parviz Rezaei,
Volume 17, Issue 44 (3-2017)
Abstract
Among the various processes that destroy lands, soil erosion is a complex and hazardous environmental process that constitutes a serious threat to preservation of soil and water resources in Iran and has inflicted its negative effects on the vital ecosystem with the intensified utilization of nature by human beings. The present descriptive and analytic research employed the PSIAC model to study erosion and compare it with other empirical methods and models by investigating the effects of nine important and influential factors in soil erosion and sediment production in various parts of the Sefidrood Basin through giving intra-layer numerical scores to them. Erosion and landform zoning maps and also zoning maps for the nine factors were then extracted. Results indicated that 77 percent of the lands in the plain landforms faced very little erosion and 23 percent little erosion, 14 percent of the lands in the mountainside landforms were exposed to very high erosion rates, 55 percent with high erosion rates, and 31 percent with average and low erosion rates, and 17 percent of the lands in the mountain landforms experienced very high erosion rates, 58 percent high erosion rates, and 25 percent average erosion rates. In other words, the rates of erosion changed from low in the plain landforms to very high in the mountain landforms. This implies that pastures and natural resources are confronted with numerous problems. In general, considering the study carried out on the nine influential factors in the soil erosion model (the PSIAC model), we notice that the mountainside and mountainous regions are more sensitive to erosion and influential factors in erosion are more active in these regions.
Shahram Bahrami, Nadia Baghaei,
Volume 18, Issue 48 (3-2018)
Abstract
Landforms and geomorphological processes is the most important factors that affecting dispersion and quality of building materials. Case study, consisting of both new and old alluvial fans is located in the West of the city of Sabzevar. The aim of this study was to investigate the process of freezing and thawing in the durability and quality of materials taken from the alluvial fans old and new. To achieve this goal, we dug four wells in different parts of new and old of fans. The examples of large and small stones from the depths of one meter, two meters, three meters and four, wells were removed. Then to measure resistance of material, against freezing and thawing, freezing and thawing tests were performed on all samples. According to the test on three outcomes for this study was obtained. First: weight loss of samples of the new fans of head is greater, compared with other samples are taken because of the waters. Second, samples of the new fans head because the waters have greater weight loss compared with other samples are taken. Therefore, samples of new fans is fine-grained as possible. Thirdly, if the target is high-quality materials, best materials is made of metamorphic minerals, such as andesite and pyroxene.
