Mohammad Reza Sarvati; Kazem Nosrati; Shima Hassanvandi; Babak Mirbagheri
Abstract
Landslides and slope instabilities are major hazards for human activities often causing economiclosses and property damages. Sikan River Basin (Ilam province) due to the topography, tectonic,lithology, and climate has enough potential for occurrence of this phenomenon. The objectives of thisstudy were ...
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Landslides and slope instabilities are major hazards for human activities often causing economiclosses and property damages. Sikan River Basin (Ilam province) due to the topography, tectonic,lithology, and climate has enough potential for occurrence of this phenomenon. The objectives of thisstudy were to determine effective parameters controlling the landslide occurrence and to preparezonation map of landslide risk in Sykan River Basin. In view of this, 11 geophysical characteristicsincluding (height, slop, slop direction), geomorphologic (the slop of land surface), geology (lithology,the distance from the fault), hydrography (the distance from the river), coverage, land use (land useand the distance from road, the distance from village), pedology (soil texture), and dependent variable(landslide distribution) were selected an independent variable and were analyzed using logisticregression model. The results showed that the influential factors on landslides occurrence in the basinare the distance from river, land use, the distance from village, the materials (lithology), slope, and theshape of land surface. Finally, the study area was classified into five major area based on landslideoccurrence risk which 19.1 km2 of total area had very low risk, 15.9 km2 had low risk, 14.9 km2 hadaverage risk and 14.6 km2 had high risk and 9.1 km2 had also very high risk. The model evaluationshowed a high accuracy 74.2% in the study area. The results of this study can be useful for landsliderisk management and for controlling the accelerated parameters.
M Ghorbani; A.A Mehrabi; M Servati; A.A Nazari Samani
Volume 63, Issue 1 , June 2010, , Pages 75-88
Abstract
Nowadays, population growth and on the other hand resources limitations astonish authorities. Population changes cause variation in economic activities and land use changes. As a whole, overusing, improper land use and human disturbances over natural resources make environmental imbalances worse. In ...
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Nowadays, population growth and on the other hand resources limitations astonish authorities. Population changes cause variation in economic activities and land use changes. As a whole, overusing, improper land use and human disturbances over natural resources make environmental imbalances worse. In recent decades, we have seen land use changes in Taleghan basin. Land use changes were produced by many factors, e.g. in abandoned lands, some parts of the region have been converted to residential areas and constructions. Since one century before, because of vicinity to population centers like Tehran and upland condition, this region has been a suitable place for recreation of travelers. Also one of the most important factors has been changed in population which has occurred in Taleghan. So that the statistical information shows substantial decrease in villages population in Taleghan. Similar to the, other regions in Iran, landuse changes especially in rangelands, is an important subject in Taleghan too. This paper tries to illustrate the relationship between population and land use changes in the given region of study and to detect the land use changes in a 15-year period. For determining the landuse, we used geographic information system and statistical methods, remote sensing also landSat images for 1987 and 2001 together. Population size were gained and analyzed for computing the population growth rate. According to what we concluded, in abandoned lands in given region of study the growth rate was positive and in other word, it increased and for other land uses this rate was negative together with negative increasing in all villages, therefore the population decreased. The villages of this region according to their magnitude of reduction in population growth and abandoned lands are: Gateh deh, Narian, Noviz oliya, Dizan, Jovestan, garab, Orazan, Nesa Bala, Mehran, Khachireh, Drapy. Thus, great number of settlers during these years migrated and the population decreased and following this trend, great area of rangelands (37.88%) which has already converted to rain-fed lands, has emerged in the form of abandoned lands in this region. In Gateh deh village, the area of rangelands had the maximum reduction and on the contrary, abandoned lands had the maximum amount of growth. Finally, it could be inferred that, there is a logical relationship between population growth and the area of abandoned lands.
