Investigation of Effective Factors on Landslides Occurrence and Landslide Hazard Zonation – Case Study Shirin Rood Drainage Basin, Sari, Iran
Kelarestaghi. A1
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Abstract
In drainage basins of northern part of Iran, combinations of natural and human factors have caused numerous landslides and a lot of damage due to laudslides. For restricting the activity of landslides are of the main solution is to avoid these regions. For doing this, landslide hazard Zonation map of the area should be prepared and low hazard and high hazard zones should be separated. In this research nine following factors were recognized as effective factors in landslide occurrence: slope, aspect, altitude, rainfall, land use, geology, distance from faults, distance from roads and distance from main drainges. Aftar overlaying landslides distribution map with the map of the above - mentioned factors, it was recognized that aspect and distance from main drainage have little effect on landslide occurrence. Then by considering the other seven factors, landslide hazard zonation of the area was done using two following methods of valuing area accumulation and Index Overlay. The result of this research have shown that in all two methods the regions in which land use changes have occurred seriusly, belong to high hazard zones and inversely, region in which forests have not been destroyed, belong to low hazard zones. After this phase the evaluation of zonation methods was done. For doing this, was used from the methods of accumulation ratio in each of hazard classes. The result of this method has shown that in Index Overlay method, different hazard zones were separated better.