M Agh-Atabai
Abstract
The Golestan province lies on one of the seismically active zones of the world. The occurrence of numerous historical and instrumental earthquakes in this area indicates its high seismic activity. Therefore, it is necessary to study its seismicity using different methods. In this research, the mono and ...
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The Golestan province lies on one of the seismically active zones of the world. The occurrence of numerous historical and instrumental earthquakes in this area indicates its high seismic activity. Therefore, it is necessary to study its seismicity using different methods. In this research, the mono and multifractal analyses have been applied for quantification of earthquakes pattern in the GolestanProvince. For this aim, the correlation dimension, generalized multifractal dimensions and singularity spectrum f (αq) have been calculated using the correlation integral and fix-mass methods. The epicentral analyses of earthquakes showed that their distribution has two scaling ranges with two different patterns and mechanisms controlling the earthquake pattern in these scales. It seems that the movements of small faults and fractures, which caused increasing the correlation dimension (1.84) and heterogeneity of multifractal structure, controlled the small scale. However, at large scale, the distribution of earthquakes is mostly controlled by the main structural trends, which in turn results in becoming almost linear their correlation dimension and also more homogeneous multifractal structure.
N. Hafezi Moghaddas; G. A. Kazemi; H. R. Amiri Moghaddam; R. Sanchooli; F. S. Hejazi Nejad
Abstract
Olang Coal Mines in the Ghareh Chai watershed are located 100-130 km far from Gorgan and 20 km to the south of Ramian. In this research, the environmental impacts of these mines in this region including impacts on soil and water resources, slope instability and river bed erosion have been investigated. ...
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Olang Coal Mines in the Ghareh Chai watershed are located 100-130 km far from Gorgan and 20 km to the south of Ramian. In this research, the environmental impacts of these mines in this region including impacts on soil and water resources, slope instability and river bed erosion have been investigated. To evaluate the effects of mine drainage and surface pollutants, 34 water samples were collected in two different seasons, spring and summer. The samples were collected from mine drains and upstream and downstream of the junction points of such drains with streams, and subjected to analysis for chemical constituents. The results have shown that mine drainage has increased salinity and organic content of natural streams, but it has not significantly affected the concentration of heavy metals and other constituents. The most polluted samples are those located close to the dumps. This suggests that improper disposal of mine dumps, which are extensive in the area, is the main cause of soil and water pollution. Therefore, proper sealing of such dumps and optimum management of mine drainage is needed to minimize the negative impacts of coal mining. To evaluate the slope instability and land sliding associated with mining activities, first of all, the position of all land slides were located and mapped. The causes of each landslide were then identified. The analysis shows that land sliding is more common in the mining areas, and human activity together with natural causes such as geology, climate and hydrology play important roles in the occurrence of landslides.