نشریه جغرافیا و مخاطرات محیطی
پیاپی 40 (زمستان 1400)

The Karvansara fault zone is located in north of the Nobaran and in the Central Iran geological and structural zone. This zone is located at the south of the Caspian Seawithin the Alpine-Himalayan belt.The aim of this study is investigation of the morphological evidences and evaluation of the relative tectonic activities along Karvansara fault zone. For this purpose, in this study, five morphometric indices including drainage basin asymmetry factor (Af), transverse topographic symmetry factor (T), stream length–gradient index (SL), ratio of valley floor width to valley height (Vf) and hypsometric integral index (Hi) as well as fractal dimensions of faults and drainage network have been calculated. Assessment of these indexes and the overlap of their results with each other and evaluation of the index of relative tectonic activity (IAT) show that most of the study area indicate very active to active classes of the relative tectonic activity. Also, calculation the fractal dimension in eleven boxes in the study area for the faults and drainage network by square method, drawing of the log-log diagrams and the use of relevant fractal analysis show the tectonic activity of the region. The neotectonic study of the Karvansara fault zone and the location of the basins with moderate to high tectonic activity, along the major active fault zones, especially in areas where fracture density is higher than other regions and fractal dimensions calculated for the fault zone and drainage network indicate activity of the fault system is on the southern part of the study area.

The purpose of this study is to investigate of the effective factors on the flooding of Gorganrood river in Aq’Qala county. In this research 18 sub-criteria that plays an imperious role to create the flood inundation were identified. The sub-criteria were compared in pairs using the AHP method and their final weights were determined using Expert Choice software. Topographic and morphological sub-criteria with weights of 0.353 and 0.333 respectively, had the greatest impact on the occurrence of floods in Aq’Qala county. Based on the results, 14.19% of the area of Aq’Qala county located in a very low hazard zone (the western and the southern regions due to their suitable topography and distance from the Gorganrood river), 18.1% in low hazard zone (the northwest of the Aq’Qala county due to the existence of swampland and salty areas), 11.95% in moderate hazard zone (the north of the Aq’Qala county due to the swampy and hilly nature of the areas and the south of the Aq’Qala county), 29.66% in high hazard zone (the southeast of Aq’Qala county due to near the Gorganrood river buffer zone and tributaries of the Qarasou river, and the west of Aq’Qala county due to the unsuitable morphological conditions and very low slope Gorganrood bed river), 26.1% in very high hazard zone (The middle of Aq’Qala county due to the topography of the plains and qualitative buffer zones of the Gorganrood River due to the unsuitable morphological conditions). Canalization of the outer arch meanders at the SallaqYilqi village to Gangirma village. Widening and dredging the channel near the Aq’Qala’s bridge in the Aq'Qala city center. Drainage and digging the detour channel according to the topographic conditions in the middle plains of the Aq’Qala county can be very effective actions to reduce the flood hazard in the Aq’Qala County.

For considering the effect of drought stress on some morphological and biochemical changes in two pumpkin species, Cucurbita maxima L. and Cucurbita pepo L. a kind of experiment was done by field culture in three water dispersal levels with field capacity, 2/3 field capacity, and 1/3 field capacity, based on the factorial design in random block form with four replications. The results indicated that increasing the stress level, leaves water potential under drought stress decreased in comparison to the control sample in both species. But with increasing drought stress, root length increased too. Also during drought stress, root soluble carbohydrates content, ascorbic acid content, dehydroascorbic acid, catalase, polyphenol oxidase, and peroxidase enzymes activity increased significantly in 5% level, according to the results with increasing the stress, soluble carbohydrates content decreased in leaf.

Spatial-temporal pattern modeling of forest cover changes provides valuable information for better understanding the change process, determining the effective factors of areas under change. In this study, we have tried to identify the factors affecting the reduction and destruction of forests in western Iran by using the capabilities and capabilities of modern technologies, including remote sensing, and then Implement in the form of a suitable computational model as a mathematical model based on the behavior of nature. In this study, in order to investigate the reduction of forest cover in Sardasht city of West Azarbaijan province, was used from satellite images of MSS, ETM+ and OLI for the years of 1977, 2000 and 2018. The above images were preprocessed and processed and then classified into two categories of forest and non-forest. The logistic regression method was used to study the relationship between forest cover reduction and physiographic and human factors. In order to obtain the lands suitability map, a logistic regression relationship was established between the forest cover reduction map from 1977 to 2000 and 2000 to 2018 and also factors affecting it. Finally, a simple spatial model was proposed that was able to predict the spatial distribution of forest degradation using logistic regression. The results showed that in the course of 41 years, about 33721 hectares had been reduced from the level of forests of Sardasht city. According to the results, it was determined that from topographic variables, parameters of distance from the road and distance from the village had the most impact on the forest degradation rate.

Experimental erosion estimation models have been developed for a specific area and their calibration is necessary for use in conditions other than their location. Examining the accuracy of experimental models for estimating erosion can lead to better estimates of sediment load and thus better design of soil and water conservation operations. Therefore, identification of high risk areas of erosion to control and reduce erosion and sediment productionIt is necessary. The purpose of this study is to investigate the accuracy and capability of ICONA models, support vector machine, field and random forest in estimating erosion. First, digital layers of effective variables in erosion including slope, geological formation, land use, soil, height, slope direction, surface curvature, waterway network density, distance from waterway, fault density, distance from fault and topographic moisture index (Twi) Turned. In this study, in order to compare different models, statistical indices of correlation coefficient (R) and absolute error (MAE) have been used. The results showed that among the mentioned models, the support vector machine model, ICONA and random forest with M7, M9 and M12 patterns had the highest accuracy with correlation coefficient (0.899), (0.845) and (0.921). And has the lowest mean absolute error value (MAE = 0.711), (MAE = 0.721) and (MAE = 0.628). According to the study of effective factors in soil erosion model, it is concluded that the parameters of slope, geological formation, land use, soil, distance from waterway and topographic moisture index (Twi) are more sensitive to erosion and the factors affecting erosion in These areas are more active.

Nowadays, due to the large amount of funds allocated to the reform clauses in the construction of watershed management projects, the review of priorities in locating critical points before the implementation of structures should be done comprehensively and accurately. Accurate knowledge of erodible points and effective factors in it is a necessary measure, which can be minimized by timely watershed management measures, whether structures or other structures or a combination of them, the severity of damage caused by erosion and sedimentation of basins. Therefore, careful selection of priorities and policies in the activities of watershed structures has a significant impact. In this study, which was carried out with the aim of basic management and planning, lattice-stone structures in Khorramabad city in order to control erosion and sediment from four criteria: hydrological, topographic, economic and social and other indicators related to erosion and fault, which are 14 sub-indicators. By using the network analysis process to weight these parameters and enter it into the GIS. 0.14, 0.141 and 0.126, which can be used to prevent the risks of erosion and sediment, which is visible in 4.5% of the study area.

In general, according to the general objectives of this study, which is to identify the points of formation of lattice-stone structures and its roles in reducing damage caused by floods, erosion and sedimentation in villages, roads, farms, gardens, etc. Prevention of life and financial injuries According to the present study, a scientific, appropriate and simple solution has been presented.Keywords: check dam, location, Khorramabad, network analysis process.

The resilience of urban systems as the best form of human habitation has significant environmental impacts, and the promotion of sustainability and resilience in cities and human settlements is a priority; The resilience of a city and how it measures in cities is important. However, despite the significant advances made in recent years in this field, Existing methods for measuring resiliency city, Only to analyze it for specific disorders, or from the perspective of resilience engineering. Based on the necessity of this research, using PROMETHEE modeling, the first step was to identify the basics of earthquake crisis management, and in the next step, Ilam analyzed the statistical analysis. It should be noted that the current research is a developmental-applied approach and research method is a combination of methods (descriptive, analytical, library and field). Also, for the analysis and drawing of GRAFER, EQS, EXCEL and ArcGIS, VPLS and AMOS-SPSS software, other applications have been used. The results of the research have shown based on GAIA layout only areas 12, 3, 8, 5 and 6 are the most resilience city than other areas. And in terms of the three criteria indexation of facilities and equipment, green space and transportation in the city of Ilam, this space has been created. Also based on a resilient network pattern phi rate positive area 12 Ilam 0.81% and the amount of phi the negative is 19/0. Finally, based on the low ranking of the PROMETHEE model area 12 Ilam in 0/6231 percent the most resilient and area 9 Ilam in -0/4306 percent the most vulnerable urban area.

In recent years, the study of the concepts of resilience at the urban and regional scales has attracted special attention, although the level and number of these studies at the urban scale is higher than studies at higher scales. Hence, the gap of this group of studies in the field of regional studies is obvious.

The main purpose of this study is to investigate and evaluate the resilience of Karaj communication network. In this research, with library studies, important criteria and sub-criteria in increasing the resilience of roads have been identified and then studied and evaluated in selected axes. The six criteria developed in this study are equestrian resilience, pedestrian and cyclist resilience, natural disaster resilience, efficient transportation management, resilience against adverse weather conditions and resilience against crime.

This research is of applied type. On the other hand, the research method is descriptive-analytical with a combined (quantitative-qualitative) approach

One of the proposed solutions to improve resilience is to walk the busy pedestrian sections of the street, implement traffic plans such as pairing and individualizing, controlling the speed of vehicles and providing safe movement for pedestrians through relaxation methods, using speed control tools. He mentioned the construction of overpasses or underpasses for pedestrians in high-risk areas, etcOne of the proposed solutions to improve resilience is to walk the busy pedestrian sections of the street, implement traffic plans such as pairing and individualizing, controlling the speed of vehicles and providing safe movement for pedestrians through relaxation methods, using speed control tools. He mentioned the construction of overpasses or underpasses for pedestrians in high-risk areas, etc

Drought Hazard is one of the natural features of the planet that can occur in all climatic zones. This study aimed to analyze the time series of agricultural drought in Darab city over 20 years (2000 – 2020) using remote sensing and satellite images in the Google Earth engine system. Satellite imagery includes 460 images of land surface temperature (LST) and vegetation (NDVI) MODIS satellites are Terra which are used to calculate the temperature condition index (TCI) and vegetation condition index (VCI) was used. Also, using the recorded rainfall data of the Darab synoptic station, the SPI index was calculated by MATLAB software in different time intervals. The results show that according to the Extreme dryness class and based on the TCI index of the 2000 year with an area of 225.46 square kilometers and also according to the VCI index of the 2013 year with an area of 280.80 square kilometers, They had the most land area in Darab city. As a result, comparing the numerical value of SPI index for each of the years of the period under study with the amount of non-drought areas obtained from TCI and VCI indices obtained from satellite images, The highest correlation coefficient of 0.76 was observed between the 12-month SPI and the VCI index, which indicates the VCI satellite index as the optimal index indicating the drought situation in Darab city. Another outstanding result of the present study is that the use of remote sensing data and Google Earth Engine system to monitor and investigate drought in areas that do not have observational data from land surveys is very useful.

Numerous human and natural factors are involved in the creation of thermal islands. Accordingly, the purpose of this article is to analyze the occurrence of heat wave in Abadan city and its impact on thermal islands. Heat waves were identified using the 95th percentile index and its application to daily maximum temperature data during the period 1985-2017. Among the heat waves that occurred two waves with more continuity during the hot and cold seasons of the selected year, their satellite images were received from the MYD11A2 MODIS sensor's product during the day and night. Thermal islands were used in Abadan city. Land use map with 4 land use classes was extracted from MOD12Q1 MODIS sensor product by supervised classification method. The results showed that the average incidence of hot flashes in each month of the year is between 3 and 8 waves. The most persistent heat waves occurred in the period of 6/11/2010 to 6/16/2010 and 19/3/2008 to 27/3/2008 with a duration of 6 and 8 days, respectively. Thermal islands in Abadan have specific spatial and temporal fluctuations and the amount of surface temperature is higher in the warm season. The high temperature in barren lands is due to the increase in fuel consumption of 2 hours per day and in the industrial area due to the burning of fossil fuels and the production of polluting gases, which causes the greenhouse effect, heat intensification and Eventually the high density of the islands is thermal and intensifies the effects of heat waves.

Return periods and the probability of occurrence of precipitation are two important indicators in studies related to flooding and precipitation, and a correct understanding of these two indicators can play an important role in climate risk studies. This study aims to investigate the performance of the Multi-Source Weighted-Ensemble precipitation (MSWEP) and to use it in determining the return periods and the probability of annual precipitation in Iran. For this purpose, the generalized extreme value (GEV) method was used. Four statistics of RMSE, MBE, PBIAS, and R2 in Köppen-Geiger climate classification in Iran were used to evaluate the MSWEP data. The results showed that this data has the best performance in arid and semi-arid regions of the country with a PBIAS of 0.40 and 0.32. In contrast, this data showed the least performance in two rainy (Cfa) and mountainous areas (Dsb). So that the maximum PBIAS between the climate zones of the country is seen between -2.45 and -0.09% in the above-mentioned zones, respectively. The results showed that the maximum probable precipitation occurs in periods of 1 to 15 years in the northern coasts and its maximum intensity occurs in the southern coasts of Iran. The probability of occurrence of precipitation in Iran fluctuates between 2.03 to 32.02%. Decreasing latitude from north to south and decreasing height from west to east is associated with a decrease in the probability of occurrence of precipitation in Iran. Maximum uncertainty is seen in the mountainous regions of Iran with a high probability of occurrence of precipitation.

Temperature hazards assessment of Khuzestan provinceAbstract: Temperature hazards assessment of Khuzestan provinceand drawing a zoning map using (GIS), four temperature risk zones (low risk, medium risk, high risk and very high risk) Revealed in the province. A) Low risk area: with the northwest-southeast trend of the province, including mountainous and relatively highlands on the Zagros highlands at the eastern and northeastern extremities. B) Medium danger zone: including low altitude belt adjacent to Zagros mountain range in the southeast; East and North c) High risk area: including low, central, eastern and western lowlands of the province d) High risk area: which covers most of the central and western areas of Khuzestan.Key words: Environmental hazards, temperature, indexing, cluster analysis.

temperature is one of the most prominent and important climatic elements that controls other environmental phenomena, especially factors affecting human activities, and is also in control of other factors such as altitude. Temperature, as a thermodynamic and important atmospheric parameter, is the source of many physical, chemical, environmental and climatic changes. Examining the occurrence of heat waves as a symbol of atmospheric hazards, along with global warming, is one of the environmental challenges of the present century. Due to the importance and effect of temperature on environmental conditions and also its role in creating and diversifying ecosystems and controlling optimal living conditions, it is necessary to study its behavioral changes in long-term (process) and short-term (phases and cycles)..Khuzestan province is located in an intermediate region in terms of climate (between the Zagros highlands in the east and north, the Arabian desert and the Red Sea in the southwest and the Persian Gulf in the south). Khuzestan due to special geographical conditions, its location in the tropics or high-pressure subtropical belt, during the year is attacked by air masses and synoptic systems with different origins and different physical characteristics that enter the region, causing diversity and change in water. The weather in the province includes temperatures. Climatic conditions in Khuzestan province and high temperatures are one of the factors limiting development in the province, so that lack of proper planning and providing facilities and facilities appropriate to the climatic conditions in the province can be a major obstacle to development. The study of temperature hazards as one of the important and influential parameters of climate, is necessary and can pave the way for national, regional and local planning.

in the present study, using the annual temperature data of 11 stations in the province during a period of 25 years (2013-2017), Khuzestan temperature hazards were analyzed. The maximum daily temperature of the hot period of the stations of the province was extracted from 15 May (October 5) to 15 October (October 5) during a period of 156 days for each year and for a total of 24 years equivalent to 3744 = (24 * 156) days for each station. Raw data of maximum daily temperature were prepared. Then, in order to distinguish hot, very hot and superhot days, the average and long-term standard deviation of the total station data during the period of 3744 days were calculated and the standardized maximum daily temperature index was calculated for all stations. Days with a positive anomaly of more than 1.5 as hot cloud days (more than 48.3 degrees), days with an index anomaly between 1 to 1.5 as very hot days (46.6 to 48.3 degrees) and days with Anomaly of less than 1 index was determined as hot days (43.28 to 46.6). Then cluster analysis was performed by cumulative stapling method on the temperature data matrix of 3744 * 1144.Discuss: the study of temperature hazard zoning map in Khuzestan province shows four hazardous zones in the form of four categories: low, medium, high and very high.Low risk: This area is observed with a northwest-southeast trend at the eastern and northeastern tip of the province (adjacent to Chahar Mahal). This temperature zone can be considered as representative of the mountainous areas of the province that mountainous and relatively highlands, including the cities of Lali, Indika, Baghmalek and Izeh in the east and northeast of the province have spread to the Zagros highlands.Medium risk: This area includes a low belt adjacent to the Zagros Mountains in the southeast; East and north of the province include the cities of Omidieh, Ramhormoz, Masjed Soleiman, Andimeshk, Dezful, Behbahan, Ramshir, Hindijan and the coastal city of Mahshahr. This area can be considered as a representative of the mountainous areas of the province.High risk: This area can be considered as a representative of the lowlands of the province, which includes the cities of Haftgol, Ramhormoz, Gotvand in the center and east and the cities of Shush, Azadegan plain and Hoveyzeh in the west of the province.Very risky: Most temperature hazards have occurred in the central and western part of the province. The high-risk area is spread in central and southwestern cities, including Abadan, Khorramshahr, Ahvaz, Shadegan, Karun, Hamidiyeh and Bavi. In fact, this area should be considered the tropical part of the province. Lack of clouds, humid atmosphere and hot south winds are the causes of extreme heat in this area. In the southern parts, atmospheric humidity from the Persian Gulf is also effective in the temperature of this region.

temperature risk study of Khuzestan province revealed that the occurrence of temperature hazards is one of the prominent features of Khuzestan province that is affected by geographical factors such as proximity to the Persian Gulf water mass, variable latitude and dispersion of unevenness and heterogeneity of inlet pressure systems in different seasons. It has a relatively high spatial diversity. Studies have shown that by reaching higher temperature thresholds, the spatial and spatial behavior of co-hazard zones reveal more heterogeneity. The least dangerous temperature zone of the province with northwest-southeast trend in the eastern and northeastern part of the province (adjacent to Chahar Mahal) has spread on the Zagros heights and the most dangerous temperature zone of Khuzestan in central and southwestern cities of the province including Abadan, Khorramshahr , Ahvaz, Shadegan, Karun, Hamidiyeh and Bavi are observed.