نشریه تحلیل فضایی مخاطرات محیطی
سال چهارم شماره 4 (زمستان 1396)

Dust is one of the common processes of arid and semiarid regions that its occurrence frequencies has increased in recent years in Iran. The proper identification of sand and dust storms (SDS) is particular importance due to its impact on the environment and human health. So far, several methods for identifying these sources have been proposed such as methods based on field studies and geomorphologic studies, as well as methods on the basis of a numerical model of air flow simulation. Therefore, identifying the process of land cover changes and changes in suspended particles in the air can help to identify the correct sources of sand and dust. Also, to manage the reduction of dust, it will be very useful to analyze the trend of changes in sand and dust sources. This data can provide some useful information to the decision makers about the future occurrence of sand and dust storm and control it. Satellite-based remote sensing is an appropriate tool for examining changes in the surface conditions of the earth over time. Satellite sensors are well suited for this purpose because of the fact that constant measurements can be repeated on a fix spatial scale. Therefore, in this research, we have tried to test different remotely sensed data time series for validation of the identified SDS sources using the latest remote sensing techniques and their integration with other information.
The aim of this study is to validate the identified dust generation sources in Alborz province using time series of satellite data and meteorological stations data. In first step, OLI data of Landsat 8 during the years 2013 through 2015 were used to make maps of vegetation cover, soil moisture and land cover sensibility to wind erosion. These maps were combined with geology and roughness indices by multi-criteria evaluation method to obtain a map of sand & dust source potential areas. Also, based on the location of the intersection of the air flow with the surface of the earth and the application of masks of non-wind erodible areas on them, probable sand and dust sources were identified. These regions were integrated with the map of sand & dust source potential areas using the MCE method (WLC) and based on a stratified random sampling plan, susceptible sites of sand & dust sources were identified. Then in this research, the time series of satellite data and weather stations data were used and the trend of vegetation, soil moisture and surface temperature at the location of identified areas during a 15-year period were monitored. Product of LPRM_TMI_DY_SOILM3 from TMI sensor, data of 16-day vegetation, 8-day land surface temperature and data of aerosol optical depth from MODIS sensor were received. Also ground- based data of dust from synoptic and air pollution monitoring stations were received. Changes Trend analysis of soil moisture, temperature and vegetation cover was done during the period. Also aerosol optical depth in dust events with high concentration was evaluated for possible sources. In addition, the areas with higher dust optical depth than other areas were identified during the period. Finally, identified sources was validated using ground- based data of dust.
The result of trend analysis showed a significant decrease in vegetation, soil moisture and land surface temperature at the place of possible dust sources during the studied period. Decreasing temperature in the southern part of Alborz Province and west of Tehran province was associated with higher frequency of dust in the area that shows why dust events has high frequency. Study of time series of aerosol optical depth data showed that concentration of dust is at or near the detected sources and the high concentration in this area is indicating identified areas are accurate. Checking optical depth in the event of high concentration and checking concurrent of air direction showed the detected sources has been correctly identified. Also Integration of dust information of synoptic and air pollution monitoring stations with the wind direction confirmed the high accuracy of identified dust sources.
Overall, findings showed the ability time series of remote sensing data to validate dust storm sources. The results of the analysis of the time series of the satellite remote sensing data showed that the surface temperature as an important climatic parameter can be well used in the identification and validation of sand & dust sources. Based on the results of this analysis in areas where the frequency of sand & dust storm events is high, there is a significant decrease in the surface temperature. This is particularly evident in the annual maximum surface temperature in the southwestern part of Iran, an area that is considered to be the predominant trajectory of sand & dust storm.

The earthquake is a natural disaster, causing the most damage to structures and lifeline. For this reason, in structures and lifeline, estimates of damages caused by the earthquake are considered and designed in the plan. The earthquake in Iran has a dominant risk among natural disasters. During the past century, Iran experienced an earthquake of magnitude 7.5 magnitudes and more. The center of most historical and recorded earthquakes is located along two hilly and young belt bays (Kopet Dagh and Alborz Mountains) and southern (Zagros Mountains with the north-west-south-east trend). The focal point of most historical and recorded earthquakes is located along two chain belt of northern (Kopet Dagh and Alborz mountains) and southern (Zagros Mountains with the northwest-southeast trend). The classification of the relative risk of earthquakes in different regions of the country in the 2800 bylaw indicates that about 73% of the country's railways network are located in areas with a high risk of earthquakes and mountainous areas, especially the Zagros chain, are at increased risk of seismicity. Construction of railway lines between Isfahan and Ahvaz is at the study stage and in this study, the risk of the railways has been investigated against earthquake.This railway passes through the Zagros mountains and has bridges, tunnels and bends. The earthquake is a natural disaster that most damage to structure and lifeline. For this reason the structures and lifeline, earthquake loads shall estimate and in order to provide its design. It should be noted that Iran in recent years, an earthquake with a magnitude of 7.5 Richter scale or more frequently experienced. Focus most historical and instrumental earthquake is located along the northern margin of two young belts (Kope-Dagh and Alborz Mountain) and south (Zagros Mountains to the northwest - southeast). The relative risk of different regions in the 2800 earthquake building and Housing Research Center Indicate that is about 73 percent of the main railway network in the regions with high relative risk and especially the Zagros mountain areas are the greater risk of earthquake. This research has studied construction of railway between Isfahan and Ahvaz against earthquake risk. This path also passes through Zagros Mountain and included bridges, tunnels and numerous curves.
Data and The Railway between is located between Isfahan and Ahvaz cities. More than 350 earthquakes occurred in the area during 1050- 2011 years. The biggest earthquake with a magnitude of 6.8 Richter took a place in 1384. There are 615 faults in this area and the biggest reverse fault zone of Zagros is perpendicular to that direction. The important characteristics of this zone are that they consist of various geomorphologic units including high Zagross (Lordegan - Brojen), Zagross folded (Baghmalek - Lordeghan) and Khuzestan plain (Ramhormoz - Ahvaz), in addition they covered from different geological units. The beginning and end of the railway in Ahvaz passes out the young sedimentary soils and not consolidate and in the Zagros that most of the diversity of geological sedimentary formations have been broken by numerous faults. In this research considered vulnerability of the railway in the seismic zone. In this research Geological maps 1:100000, LISS III images of IRS satellite, recorded and historical earthquakes and path of railway were used. In the first stages of investigation the earthquakes based on semivariogram model and Kriging interpolation method converted to seismic map. Then the Fault lines have extracted of geological maps. Slope, Curvature, Profile and Hypsometric diagram were calculated based on digital elevation model of Aster data. Lineaments, landforms, landuse and vegetation cover were prepared from LISS III images of IRS satellite. The layers were standard by fuzzy membership. Then, they have combined based on Gaussian fuzzy membership function. Final integration was done by 0.7, 0.8, 0.9 and 0.95 gamma and the result was asseted by zonal statistics method.
Result and Seismic zones on the basis of semivariogram model and Kriging interpolation method showed that railway in three reaches is facing to earthquake with about 4 Richter. Whereas the earthquakes greater than 4.5 Richter are located on quaternary alluvial deposits, in addition the maximum magnitude of earthquakes on faults and lineaments as well as on the difference formations. The case study is Iran’s biggest fault zones and more than 350 earthquakes occurred during 1000 years. The fault, earthquakes and also historical earthquakes layers, indicates active seismic region. Density of vegetation, landuse, seismic layer, slope, Curvature, Profile, faults and lineaments and drainage density layers, combined using overlapping functions and 0.8gamma. The zonation of risk was done in 4 classes included low risk, medium risk, high risk and very high risk. The result was shown two long part and a short part l of railway were placed at the maximum risk.
There are a great variety of topography, geology and system faults in this area. Due to that diversity, the damage of the earthquake are differently. In other words the severity of an earthquake with a constant magnitude is different. The diversity of lithology and outcrops are in two fault systems that railway pass through them, one of the Shareza to Ardekan and other the Ramhormoz to Baghmalek. So magnitude of the earthquake will be changed in path of railway.The beginning and end of the railway are most vulnerable because they passes of young alluvial sediments and isfahan and Ahvaz areas. The presence of sediments around the Gandman as well as in the railway in Izeh will be encountered with increasing mass movement by earthquake. The existence of convex domains from Dizjan to Izeh shows the severity of the earthquake in sensitive and vulnerable areas. Seismic records of more than 5 magnitudes and low depths have little effect on the risk outcomes that need to be considered as evidence of potential risk.

Statement of the problem: Thunderstorm is a destructive atmospheric phenomenon, which annually causes a lot of damage to various parts of human activities. Due to the accompaniment of thunderstorm with rainstorm and hail and its effective role in creating sudden floods, the analysis of the behavior of this hazard has been widely studied both in terms of agriculture and in terms of financial and life damages throughout the world. The study of thunderstorm as a hazardous atmospheric phenomenon using instability indexes in Iran has been less considered due to lack of observation stations. Convective Available Potential Energy (CAPE) and Vertical Wind Shear (VWS) are two indexes that are often used to describe and detect thunderstorm environments. This study evaluates the thunderstorms in Iran with reanalysis data using CAPE and VWS indexes.
Research Thunderstorm data in 7 different conditions at 8 times a day for 42 synoptic and upper air stations during a 37-year common period (1980-2016) was received from the Iranian Meteorological Organization. At first, frequency, trend and time of occurrence of thunderstorms in Iran were investigated during the statistical period. Then, the ERA-Interim reanalysis dataset of the European Centre for Medium-Range Weather Forecasts (ECMWF) with spatial resolution of 0.5 ° was used for the analysis of thunderstorms. To evaluate the ERA-Interim dataset, the CAPE and VWS values for the 80 selected thunderstorm events that were calculated using the RAOB software were compared with ERA data and their accuracy was confirmed. After confirming the accuracy of ERA data, the average values of CAPE and VWS indexes in 42 stations of the country were calculated based on 4,542 thunderstorm events at 00 and 12 GMT during the study period, and the maps of these two indexes were drawn up using the IDW method. Then, using an equation, the thunderstorm severity thresholds across the country were determined using ERA data with 4,542 thunderstorm events to distinguish between mild, severe and very severe storms. To ensure the selection of important storms, storms with CAPE values of less than 50 were removed to exclude poor environments for convection occurrence. As a result, out of 4,542 thunderstorms, 535 events were eliminated and 4007 events remained. On this basis, a "2 x 2 contingency table" was prepared that compares thunderstorm events and forecasts. This table provides the information required to compute warning performance statistics including POD (Probability of Detection), FAR (False Alarm Ratio) and CSI (Critical Success Index). But the results of these statistics did not match well with the conditions of thunderstorm events in Iran. Therefore, the discriminant analysis was used to differentiate the intensity of thunderstorms and to discriminate mild, severe and extremely severe thunderstorms.
Explain and interpret the The results of the study showed that thunderstorms in Iran are increasing during the statistical period with a regression slope of 0.23 events per year (8.5 events in the statistical period). The highest frequency of thunderstorms was observed in the month of May with an annual number of 111, and the lowest was observed in January with 12 events. Most thunderstorms occur around 21:30. The highest average frequency of annual events at stations was related to the stations of Urmia, Tabriz, Khorramabad and Bushehr respectively. The proper capability of ERA data to estimate instability indexes in Iran was proved. ERA data provides a very near estimate for VWS, but estimates for the CAPE index are slightly more than observational values. The highest values of the CAPE index are observed in southern provinces, as well as in the southwest of the Caspian Sea coasts, and the highest values of the VWS index are found on the Persian Gulf coasts. When the storm severity breakdown equation for the 400 selected storm events was obtained and the "2 x 2 contingency table" was prepared, it was found that this equation was not satisfactory with respect to the POD, FAR, and CSI indexes. Hence, using the discriminant analysis, the storm severity breakdown relationships and their discriminant equations were obtained. These equations categorized 60% of the surveyed thunderstorms correctly. There is no significant difference between the mean values of CAPE and VWS in the three storm intensity groups. The role of the VWS index was higher in determining the type of storm.

The correct management in natural ecosystems is not possible without knowledge of the health in its sectors. Vegetation is the most significant sector in ecosystem that has important role in its health. Resilience is one of the defining features of health vegetation The term resilience was first introduced in the study of ecological systems and demonstrates the ability of the ecosystem to maintain its performance in the face of environmental disorders. A resilience-based system is not only equipped with a disorder adjustment mechanism but also has the potential to benefit from changes in a way that lead to creating an opportunity for development, innovation, and updating. Therefore, when a change occurs, the resilience provides the needed conditions for restarting and reorganization. If this goes beyond disturbing forces, the system will have the power to return to the maximum vegetation density with the least erosion effects, otherwise the system will be vulnerable to the change that was created and could already be controlled. This research was done in part of North east of South Khorasan province (arid climate) with the aim of quantifying vegetative resilience on behalf of ecosystem health in response to drought occurrences and long-term precipitation changes, as environmental disturbances. Therefore first, using daily precipitation data from 15 meteorological stations around the study area, their annual precipitation was extracted and was standardized by Standard Precipitation Index (SPI) over the course of thirty years (1986 - 2015). Then, the SPI index data in 15 stations were interpolated by ArcGIS software based on Inverse Distance Weighted (IDW) method and dry, wet and normal years was estimated in the study region for each year. On the other hand, from archive of satellite images of Landsat 5 and Landsat 7, an image was created for each year in study period, between 15 June and 15 July, with permanent coverage at the best of growth. Following the necessary corrections for satellite images, the average Transformed Normalized Difference Vegetation Index (TNDVI) was obtained of each image by ENVI software. Finally, effected of precipitation changes on mean TNDVI was assessed and vegetation resilience was stabilized whit selected of sever time period samples based on four effective parameters (Amplitude, Malleability, Damping and Hysteresis). Comparison of annual precipitation variations in the thirty-year time series (1986 -2015) indicated two approximate wet and dry periods in study area. The wet period is related to the first fourteen years of the time series (1986-1999) and the dry period is related to the last sixteen years (2000-2015). In this term, severe precipitation incidents with different intensities were occurred in the study area including one case of very intense precipitation (1986), one case of intense precipitation (1991) and two cases of moderate precipitation (1996 and 1992). Also, four drought incidents were occurred including one case of intense drought (2001) and three cases of moderate drought (1987, 2006 and 2008). All precipitations (wet years) are related to the first half and most droughts are related to the second half of the studied period. In this study for fixing of vegetation resilience in study area and for calculating of its parameters, In addition to the thirty-year time series selected sever time sections. in the whole study series (1986 - 2015), maximum of mean TNDVI (49.37 %) was in 1986 (reference), the lowest mean TNDVI (43.58%) was in 2010, The year effect of the decrease precipitation and drought, and mean TNDVI in 2015 was 44.28 %. Amount of parameters amplitude, malleability and damping are respectively 5.79, 0.7 and 5.09, and hysteresis was zero (%). The result of this case showed that the vegetation has moved towards the reference state (Resilience) but has not reached to amount of reference vegetation. The most specific cases for vegetation resilience happened from 1986 to 1996 (wet period) and 2003- 2009 time sector (dry period). In the first time section amount of amplitude and malleability were 0.64 %, damping was zero and hysteresis was 0.25%. The result of this case showed that not only the vegetation was returned to the reference state but also was increased to the reference (Cross reference).So despite the reduced rainfall and occurrence of sever occurrences of drought in dry period, hysteresis parameter (0.05 %) observed in 2003- 2009 time sector too that confirmed clearly vegetation health in study area whit dry climate. Awareness of the health status of the vegetation and its response to long-term precipitation changes and environmental disorders, such as drought occurrence, ensure the success of the managerial plans for renewable natural resources. The present study is the second study on quantifying the vegetation resilience and the first study under dry climatic conditions in Asia (an average annual precipitation of 160 mm) conducted in Iran by calculating four factors related to resilience, and is the first study that has presented the factor hysteresis in the calculations. Despite continuous of difficult condition, the native vegetation of the study area has been able to return the reference state not only by resolving the disorder relatively, but also it has experienced hysteresis stage. A set of quantitative calculations showed despite reduced annual precipitation and drought events, vegetation has been able to maintain its resilience, which indicates the health of the vegetation in the studied ecosystem. With the presence of such amazing protective and consistent mechanisms in the vegetation of arid regions, it is possible to maintain and restore these regions by proper managerial plans.

Drought is a natural occurrence that occurs repeatedly or alternately and is likely to occur in almost every kind of climatic event. Also, the distinction between this phenomenon and other natural disasters is that unlike other disasters, this phenomenon gradually over a relatively long period of time to act and its effects may be delayed after a few years and more than any other natural disaster appears. Several indicators have been presented to decide the characteristics of hydrological and meteorological drought. These indicators are generally based on one or more climatic elements. The SPI and SWI indicators are similar in terms of ease in calculations and results, and use monthly precipitation data and monthly spatial data rates. The simultaneous effect of meteorological droughts on groundwater levels rarely happens. Therefore, the present study investigates the effect of meteorological droughts on the groundwater level of Marand plain and calculates the time delay of drought on groundwater level.
The study area in this study is Marand Plain in East Azarbaijan Province. In this research, we used meteorological data (average monthly rainfall) of 7 rain gauge stations during the statistical period (1980-2012), and the monthly water level data of 23 piezometric wells during the statistical period (2001-2011). The correlation between stations and piezometric wells and linear regression method was used to reconstruct the statistical defects, then SPI and SWI indices were used to study the rainfall and groundwater changes process and the analysis of drought conditions in the meteorological and underground watersheds. The SPI index is basically calculated for periods of 3, 6, 9, 12, 18, 24, and 48 months. Also, the standardized water level indicator (SWI) has been used as a criterion for assessing occur drought and wet years in the Marand plain. The purpose of the SWI index is to allow zoning of groundwater level fluctuations at the study area. Extraction of drought and wet year intensities in different scales and basin zonation for drought maps in Marand plain was first calculated by entering the monthly values in DIP software, SPI values for 12-month time series. SWI values were calculated from monthly data of piezometric stationary level surfaces, such as SPI values, with the help of DIP, Minitab and Excel software. Geostatistical Analyst was also used to decide the weather drought and groundwater drought periods for the ArcGIS software.
Conclusion and The results of the SPI values showed that meteorological drought is not of a definite local place, while groundwater droughts have not occurred randomly in the area and its concentration in the west of the aquifer is more than the east. Considering the increase in the area under cultivation, to compensate for the water needs of agricultural lands, an increase in the harvesting of underground water table has occurred in order to compensate for the need for water, indicating a tangible relationship between the rainfall and the level fluctuation in the Marand plain. Therefore, considering the increase in the area under cultivation during the years of drought in the region, the best correlation between them was -0.720 with a delay of 5 months, in order to investigate the effects of drought on the surface of the station, which was significant at 1% level It illustrates the impact of groundwater resources with a 5-month delay. Also, the results of the survey of monthly data of Marand plain surface during the statistical period (2001-2011) showed that the groundwater level of the plain had a negative trend that fell by about 2 meters.
The SPI and SWI indices make it possible to calculate the start and end times of meteorological and groundwater droughts in a steady period of information computed by these indicators, as well as the severity, duration and frequency of droughts. Drought zoning maps using SPI and SWI values in the Arc Gis environment showed that meteorological droughts, due to the characteristics of droughts, do not have a definite spatial location, while droughts Underground water does not occur accidentally in the area and their concentration has been created at specific points in the aquifer, which have tropical and human stresses (in terms of excessive and permissible withdrawal). Although the weather factor has had the greatest impact on the level of stagnation in the Marand Plain in recent years, this crisis is the result of a set of factors, including free radicals, which is itself due to meteorological droughts; therefore, due to the trend of change The level of the stand is consistent with drought changes, it can be concluded that the drop in the surface of the Marand Plain is mainly affected by drought. According to the results of this study, it seems that continuous monitoring of drought situation and strong monitoring of harvesting, especially in severe and prolonged droughts, is very necessary to prevent a significant drop in groundwater level in the Marand plain.

Drought is a recurrent phenomenon and natural hazards which can happen in all parts of the world. It has serious challenges with significant negative impacts on the different sectors. In terms of people affected, it is the number one risk of all natural hazards, with more than 1 billion people affected in the last decade. Without any doubt drought poses a great threat to households, communities and societies that are dependent on agriculture for their livelihood. For decades now, Iran has been facing droughts so severe that its government was forced to accept foreign aid for only the second time since the revolution in 1979. Many villages particularly in east and south east provinces were evacuated due to lack of water, and more than a million head of cattle perished across the country. Many farm workers lost their jobs, and, in the different part of the country, the largest body of freshwater in Iran – Lakes – ceased to exist. This situation is likely to worsen in the future, with an already observed increase in droughts and predicted increases in extreme droughts in the future due to climate change. For example, a major World Bank report confirms that this is different. Iran faces, not the familiar periodic dry spells, but a severe water crisis that is made even worse by recent high rates of population growth. Climate change, though not the cause of this crisis, is predicted to make it even worse, with per capita water availability being halved by 2050. The crisis is thus all set to turn into a super-crisis, with ever more land being taken out of production over the coming decades. However, the effects of droughts to human society depend not only on the severity of the event (such as lack of rainfall) but also on the resources the society and its members have to cope with this shock. Such resources can include formal market mechanisms as well as informal/traditional ones, e.g. from crop insurance to kinship arrangements. Consequently, dependent on the coping strategies available, the short and long term effects may differ greatly among sub-groups within the affected population.
Knowledge of what farmers do in response to these events can broaden adaptation options and improve resilience within the sector. Among other dimensions it is assumed that psychological issues play an important role in predicting farmers’ intentions and actual responses.
In this context, a study was carried out to identify the most prominent drivers of, and impediments to, drought adaptation, using Health beliefs model.
his study is an applied research and with the survey method was conducted. A sample of 320 farmers was DEHLORAN city, Illam through a two-stage random sampling was stratified. Data for this study were collected using a structured questionnaire. In designing the questionnaire, a 5-point Likert-type scaling was used, ranging from 1 (completely disagree) to 5 (completely agree).
The face validity of the questionnaire was confirmed by a group of experts.
And with Using SPSS software (version 20) The reliability of the main scales of the questionnaires was examined by Cronbach Alpha coefficients, which ranged from 0.65 to 0.90, indicating the tool of study is reliable.
The results reveal a significant correlation between adaptation behavior with the Perceived benefits, perceived Vulnerability, perceived vulnerability severity, Vulnerability perceived, self-efficacy, general beliefs and intention. Also between barriers perceived and cue to action with adaptation behavior there is negative correlation.
The results of regression analysis showed that the three variables of, General beliefs, self-efficacy and Perceived benefit could predict 58 percent of variations intention to adaptation (sig=0/01, F= 123/37, Constants=3/78). In other word these variables could predict 54 percent of variance of farmer’s intention to adaptation. we also find that General beliefs is a key predictor of intention to adaptation (Beta=0/43).
Also, the results of showed that the variables of, intention, perceived vulnerability, perceived benefits and Vulnerable perceived, could predict 21 percent of variance in of adaptation behaviors (sig=0/01, F= 21/33, Constants= 4/08). These variable could predict 21 percent of farmers’ Behavior to responses to drought. Also, Intention is most important factor influencing of farmer’s adaptation behavior with drought.
Our research contributes to farmer’s adaptation behavior with drought by exploring and identifying the complicated reasoning behind why people do or don’t adaptation behaviors. Findings of study revealed that farmers’ Behavior to responses to drought was predicted mainly by Intent, perceived vulnerability severity, perceived benefits and Vulnerability perceived. Finally, These findings can provide recommendations on factors important to adaptation with drought among farmers in Iran.

1- Landslide is considered as one of the natural disasters for human beings which makes a lot of deaths and sever property damages worldwide. Therefore, it is necessary to investigate the effective factors in order to make urgent planning and to present management solutions for the sensitive regions. In Iran, more studies on mass movements and landslide hazard zonation, is based on descriptive statistical methods, while in the world today, most studies of mass movements is based on physically-based models and mathematics and numerical methods. Therefore, in this study to analyze the stability of the hillslopes and landslide azard zonation in the study area was used physically-based (process-based) model.
Keywords: Landslide, Stability of hillslope, Process- based Model, Sinmap, Javanrood
2. Research This research was done by both field and experimental methods. Research steps are summarized as following.
2.1. Data Bank Preparation: Geomorphologic, hydrologic and soil mechanic characteristics of slopes in the considered zone were the required information in this study. To obtain this information, at first, it was necessary to recognize sample slopes to measure the above- mentioned variables. Therefore, first of all, landslides distribution map was prepared in the considered area then, on this basin, sample slopes were selected to measure essential variables. Sample hillslopes were recognized as 12 hillslopes, 5 stable (lack of land sliding) and 7 unstable hillslopes (having land sliding mass). They were 1- 12 numbers. 1-5 hillslopes are stable and 6-12 unstable. After selecting sample hillslopes, necessary parameters were assessed as following:
2.1.1. Mechanical features of soil: soil sampling from each hillslope was done the mechanical features of soil, so 50 kg soil was removed from each slope, from 75 cm to 1cm depth. In order to sampling soft and coarse soils, a core cuter devise and shovel were used, respectively. Sampled soils were transferred to Kermanshah soil mechanic laboratory, Kermanshah provincial transport office and necessary parameters, including dry soil specific weight(γ d), wet soil specific weight (γt), hydraulic conductivity , soil internal friction angle(φ) ,soil cohesion , and soil porosity were determined by using direct shear test.
2.1.2. Determining the geometric parameters of slopes: except for using topography map, altitude numerical model (Dem) with a pixel size of 20 by 20 m and satellite images were used to determine morphology parameters and to identify various hillslope types. Applying GIS software, manual and laser tape measure, clinometer, slope geometry characteristics such as mean slope (beta), slope width (W), slope length (L) area, were extracted.
2.2. Model implementation: The model used in this study was Talebi (2008) model which was, in fact, an extended model of process-oriented (physically based) model, being a combination of geometry model, hydrology model (permanent condition) and infinite slope stability theory. After obtaining necessary parameters to get slope factor of security (F S) including laboratory, topography and hydrology parameters, Fs values for each slope were measured by Matlab software
3. The findings of slope stability analytical model introduced hillslopes as unstable with FS less than 1. This hillslopes are classified as extremely high unstable. Main reason for instability is low Internal friction angle (often 25- ) and higher slope (more than 35%) and hillslopes concave longitudinal profile. Concave hillslopes drain more slowly than other slopes; consequently, soil saturation storage would increase, while stability would decrease. The results of the landslide hazard zonation mapping indicate that the majority of the study area located in protection class. So that constitutes 26% of the study area. The lowest percentage of study area belonging to the middle stability class and quasi-stable, which is) 9.2%( and( 6.2( % of the study area respectively.
4. According to the results of the study and analysis of model zoning map sinmap, it can be included that percentage of stability is less than percentage of instability in Javarood region. So that the highest percentage of area is located in the protective area (26%) and high threshold of instability (15.9%) and a lower percentage of the region is located as stable and quasi-stable (20 percent).This results indicates that the susceptibility of the scope of the study area in terms of inherent instability. So that natural factors (concave longitudinal profile and low friction, high angle of slope and high saturation coefficient) in these areas will certainly cause the landslide phenomenon. Therefore, this hillslopes will unstable under the influence of human activities such as leveling hillslope for the construction of residential or cutting their road.