H. Gharahi; B. Bohlooli; A. Sayyar; M. Shariat jafari
Abstract
Landslides cause damage to property and pose a threat even to human lives. Suitable landslide susceptibility, hazard and risk models could help mitigate or even avoid the unwanted consequences resulted from such hill slope mass movements. For the purpose of landslide susceptibility assessment, a spatial ...
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Landslides cause damage to property and pose a threat even to human lives. Suitable landslide susceptibility, hazard and risk models could help mitigate or even avoid the unwanted consequences resulted from such hill slope mass movements. For the purpose of landslide susceptibility assessment, a spatial database, which included 18 landslides prepared and analyzed using LISS-IV satellite imagery and geographical information system (GIS) technology. Analytical hierarchy process (AHP), the statistical index (Wi) and weighting factor (Wf) methods were applied to determine the significance of event-controlling parameters in triggering the landslides. The parameters included lithology, slope gradient, slope aspect, elevation, distance from faults, distance from stream and drainage density. These factors are different in geomorphic and geologic setting. The result showed that lithology, slope gradient and distance to stream play most important roles in landslide susceptibility. To confirm the practicality of the three susceptibility maps, there were compared with landslides activity map containing 12 active landslides. The results showed that the Wi method gave a more realistic picture of the actual distribution of landslide susceptibility, than the Wf method in the reservoir of Alborz dam.
M. Rajabi; B. Bohloli; M. Mohammadinia; E. Gholampour Ahangar
Abstract
The shear and compressional wave velocities (Vs and Vp, respectively) have many applications in petrophysical, geophysical and geomechanical studies. Vp is very easily obtained from sonic logs that are available in most of oil and gas wells, but some wells (especially old wells) may not have Vs data. ...
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The shear and compressional wave velocities (Vs and Vp, respectively) have many applications in petrophysical, geophysical and geomechanical studies. Vp is very easily obtained from sonic logs that are available in most of oil and gas wells, but some wells (especially old wells) may not have Vs data. In this study Vs was predicted from porosity well log data (neutron, density and sonic) using fuzzy logic and neuro-fuzzy techniques. For this purpose a total of 3910 data points from Sarvak carbonate reservoir which have Vs and porosity log data were utilized. These data were divided into two parts, one part included 2046 data points used for constructing models and the other part included 1864 data points used for testing models. The results show that fuzzy logic and neuro-fuzzy techniques were useful methods for prediction of Vs in this carbonate oil reservoir.
