Journal of Spatial Analysis

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Spatial analysis as the main approach of geography was reviewed and searched through its historical development. The results of this exploratory research showed that this approach was born after the Second World War due to the overall interest of geographers to develop universal theories and laws. The advocators of this field believed that the old regional geography was not able to develop a scientific and applied knowledge. The main motivation of the development of the spatial analysis was the quantitative revolution of the 1960’s which was triggered by the article published by Shaeffer in 1953. This was followed by some prominent geographers such as Bungeh, Ulman, Barry, Hagget, Chorley and others. Bungeh and Harvey strengthened the philosophical foundation of spatial analysis and others such as Hagget , Chorley and Hajestrand published important books in the field of quantitative geography. The main objective of spatial analysis is to analyze the distributions through the identification of their global and local structures and reasoning these structures by their spatial relationship with other distributions. In this regard it uses quantitative data and mathematical language to achieve the spatial theories and laws.

     The spatial analysis studies the spatial distributions and structures. These are the entities that are not subject to the human interpretation and thinking. This approach is true in the both physical and human geography. The knowledge it tries to achieve is the theories and laws about the spatial distributions. The methodology of spatial analysis is the quantitative methods such as experiment and survey. Thus in terms of ontology the entities of spatial analysis are independent of human mind and objective. The spatial characteristics of distributions are not constructed but discovered. The methodology used in spatial analysis is quantitative and objective including some methods such as experiment and survey. In 1980 and onward, human geography tried to move toward qualitative methods such hermeneutics but during 21^st century all branches of geography are using quantitative methods more frequently than qualitative ones; but the use of the combined version of quantitative and qualitative methods is becoming more frequent day by day.

  The introduction of Geographic Information System as the operational environment for spatial analysis works the approach has become more widespread and dominant. Geographers are now able to analyze more spatial data and discover more spatial theories to solve the spatial problems. GIS is the main tool for spatial analysis and by introducing the science of geostatistics has improved the scientific and applied power of spatial analysis. The application of quantitative geography including geostatistics and GIS requires improved knowledge of mathematics, geometry and statistics; the main language of today geography. The spatial analysis covers the important topics of geography including spatial distributions, regions, spatial relations especially the relation between human and environment, spatial structures, spatial reasoning, interpolation, and the most important topic of spatial planning. The spatial analysis is the only scientific field to define and develop spatial planning. With correct and logic spatial planning there won’t be any environmental hazards. Because in any region all human settlements and activities are planned according the potentials of the region.

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Active tectonics of the Roudbar region:
with special reference to the landslides of the area
 
Tayebeh Kiani, Assistant Prof. in geomorphology, Kharazmi University
tayebeh.kiani@gmail.com
 
Hyrdad Nadim, MSc in environmental geology, geological hazards trends, Geological Survey & Mineral Exporation of Iran
hirad.nadim@gmail.com
 
Parastoo Ghaforpur Anbaran, PH.D Student in Geomorphology, Kharazmi University
parastooghaforpur@yahoo.com
 
 
 
Extended abstract:
Introduction: Due to its specific morphology and extensive tectonic activities, Roudbar rigion has always been affected by various geological hazards such as earthquakes, floods, biological pollution and landslides, which landslide is one of the most active phenomena in the region of this vast And mountainous area. Within the Roudbar geological sheet, 11 large and small landslides have been recorded with different yields and properties, some of which have catastrophic consequences, including the Roudbar and Fatalak landslides, which occurred as a result of the earthquake of June 31, 1990 Has caused devastating events in the Roudbar area and resulted in casualties and financial losses. Extreme performance of tectonic phases, which enact a major role in landslides, construction factors, road and rail, Steep slopes of topography, Sloping Loose Materials, are a various factors in the occurrence of such landslides. Due to the fact that landslide is predictive, preventive and sustainable, it is important to identify and zoning in the country and province and Perform basic geological studies in prone araes to landslides with a large scale. Due to the high potential of the region for the subsequent landslides and the properties of the intact areas with the old landslide areas, In present research, it is necessary to determine the most important factor in landslide occurrence in Roudbar area through field investigations and based on that, plan management will happen for controlling landslide phenomenon. Eventually, using geomorphic indices, the tectonic activity status of the Roudbar region is determined, and with the adaptation of the location of landslides and faults with the tectonic activity zones map, relationship between tectonic and landslide are investigated. Also, the risk zone, where there is a probability of landslide instability, is determined.
Method: The study area is located at 45 ° 36 'to 30 '45 ° 36' north latitude and 30 '22 ° 49' to 49 ° 49 'east longitude. Roudbar is one of the southern cities of Gilan province, which has a reputation for having olive gardens, and is named after its seasonal and permanent rivers. Roudbar city leads to from north to Rasht, south to Roudbar Alamut (from Qazvin province), from east to Lahijan and from west to Fomen city.
 In the first phase, based on ground surveys and laboratory studies, the geological map in the scale of 1: 25,000 and other required data, limited area and Condition landslides are identified on aerial photos and satellite imagery. In the second phase of this research, geomorphic indicators the mountain front sinuosity index (Smf), the ratio of width to depth valley floor (Vf), Stream Length Index (SL), Basin Shape (Bs), Asymmetry Factor (AF) are used. Then, the results of the indicators are presented as a tectonic activity index (LAT).
Conclusion: Based on ground surveys and laboratory studies, the geological map in the scale of 1: 25000 and other required data, limited area and Condition landslides are identified on aerial photographs and satellite imagery. Based on this, it was found that Roudbar landslides were more affected by structural factors and weight (slope loading) has taken place. It seems Structural factors hidden in most of the landslides in the region. Based on the results of the tectonic activity relative index (Lat), most sub-basins have high and moderate tectonic activity. In term of width, the intense class includes with 195.55 square kilometers (67.21%) of the total area. The integration of different tectonic zones with the location of the landslide zones of the region, the close relationship between the zones with intense and moderate tectonic activity with the landslide zones designated in the first part of this study shows that the zones with Fatalak, Lavie, Roudbar, Filde landslides are in areas with intense tectonic activity and The landslides of Dashtgan, Talabar, Taklim, Nesfi, Dolatabad, Herzavil are located in the moderate tectonic activity zone. Based on ground surveys, the results of calculations of geomorphic indices indicate the relation between the activity of the land area and the landslide hazard. Considering the inevitability of the faults' activity and the resulting hazards, it is suggested that, in order to improve the country's substructure development, more detailed and larger scales on the landslide mechanism introduced in this research (Including determination of gradient safety factors (FS), calculation of the risk of slipping region and applying slope stability and safety methods, etc.), be done Systematicly and in coordination with organizations and related departments.
Keywords: Active tectonic, Geographic Information System, Geomorphic indices, Landslide, Roudbar.