GEOGRAPHY AND ENVIRONMENTAL HAZARDS
Year:2020 | Volume:9 | Issue:35|Papers Count:13

The geographical distribution of earthquakes shows that almost the entire territory of Iran is at risk of earthquakes and is potentially unsafe. In the last 40 years, a number of devastating earthquakes have occurred in eastern, western, northern and southern Iran. The city of Sari is three and half kilometers away from this fault and 37. 5 km away from the Alborz fault. Considering the existence of seismic faults in Mazandaran province, which can endanger the city of Sari, assessing its vulnerability using an appropriate model is necessary and unavoidable. The aim of this study was to evaluate the radius model to estimate the damage caused by earthquake in Sari. Two scenarios were considered with respect to the two faults of Khazar and northern Alborz to estimate the damage caused by a possible earthquake in the study area. Data analysis was performed according to database-based methods using the Radius model and software based on the geographic information system approach. The results showed that according to the Khazar fault scenario, 18910 buildings will be demolished, 2382 people will be killed, and 22897 people will be injured. According to the Alborz fault scenario, 3086 buildings will be demolished, 15 people will be killed and 2102 people will be injured. Due to the short distance between the Khazar fault and the study area, this fault causes the most damage to the region. The results of this study provide useful information for decision making in the city's seismic risk reduction plan.

Air pollution is now a major problem in Tehran's metropolis, which threatens the health of its citizens more than anything else. The purpose of this study was to introduce frequent and common synoptic patterns in the incidence of severe and critical pollution in Tehran. For this purpose, air pollution data were first obtained from Tehran Air Quality Control Bureau (2007-2017) and then hazardous days were identified based on AQI index at each of the stations. The rest of the NCEP / NCAR database reassessment data was obtained with a spatial resolution of 2. 5 at 2. 5 ° for sea level, 1000, 925, 850 and 700 hp. After delineating a synoptic map of the above alignments, multiple dominant and repetitive synoptic patterns have been identified and analyzed by repeated eye examinations. During the statistical period, 157 days of severe and dangerous contamination were identified. Among the pollutants affecting Tehran, the most pollutants are PM10, PM2/5 and NO2. An in-depth examination of 5 synoptic patterns revealed severe contamination: Patterns of European immigrant high-pressure, Siberian high-pressure, mixture of Siberia and Saudi high pressure, and Pakistani low pressure. In a pattern commonly occurring during warm-weather pollutions, low-pressure Pakistan played the most important role in producing severe winds in the deserts surrounding Tehran, with the most pollutants being PM10 and PM2. 5. The second pattern is caused by the cold season pollutions. In the model, the Siberian high pressure in the lower tropospheric layer (below 850 hPa) with cold advection was the main cause of stability and accumulation of pollutants and at higher levels of the Arabian high pressure stack, while intensifying stability and persistence of atmospheric conditions. In this model, cold-weather stability dominates the city of Tehran. In the third dominant pattern of high pressure Saudi Arabia and its tablets in all atmospheric layers cause very strong stability and persistence of pollution and air stability. In this model, due to the dynamic nature of the system, despite the stability, the air temperature gradually increases and conditions are quite different from the seasonal conditions.

The city of Sarakhs is located in in Khorasan Razavi province, the northeast of Iran and has a dry and desert climate. Although this city has no problem in the field of gaseous pollutants, but dust causes more unhealthy days than before. The purpose of this study was to investigate the physical and chemical properties, identify dust particles minerals over Sarakhs city and identify sources of dust storms. Spatial repetition of dry particle sedimentation has taken place during the summer and autumn seasons of 2019. This study was performed on fine round particles with a size of less than 10 micrometers at a height of 2-4 meters above the ground. Using Inductively Coupled Plasma (ICP) and XRD, metals and minerals of dust particles were identified and, then, using Scanning Electron Microscope (SEM) and Particles Size Analysis (PSA), particle shape and size were determined. According to the results, metals Ca, Al, Na, Fe, S, Ti, Ba, Mg, Zn, and Sr have the highest concentrations of dust in designated villages. The study of dust particle mineralogy showed that the dust has a terrestrial origin and is very similar to the minerals in the dust of Sistan plain and Hamoon wetland. The highest concentrations of clay minerals are: Kaolinite, Chlorite, Quartz, Calcite Gypsum. Ca and Al with the highest concentration among soluble metals indicate the origin of dust in the region. Also for elements such as Sr, S, and Gypsum, an evaporative source can be considered. The high concentrations of toxic and chemical elements including As, Pb, and Zn can be attributed to Khangiran refinery. Therefore, dust in Sarakhs region has three sources of local origin, evaporation and chemical.

Exploring active tectonics considering earthquake in different area is very important. These movements have effect on the earth and each one the effects is visible around us. This research aimed to analyze and compare the tectonic activities of two basins of Hable Roud and Kordan. In addition to field observations, 10m DEM, Landsat images, and softwares such as Arc GIS Global Mapper13 were applied to draw maps and analyze data. Applied indexes in this research were fan comicality index(FCI), width to valley height (Vf), drainage basin shape (BS), sinuosity of mountain fronts (Smf), index to assess basin asymmetry (T), drainage basin asymmetry (Af), river sinuosity index (S), and relative tectonic activity index (IAT). Through IAT, the whole outcome of tectonic activities by the above-mentioned indexes can be measured in tectonic regions. According to the IAT classification, both basins are active tectonically however the rate of tectonic activities in the Kordan basin is greater than in Hablerod basin. Active tectonic, according to IAT index in Kordan basin is assigned to class 1 and Hable Roud basin is assigned to class 2. According to IAT classification, new-tectogenesis activities is more in Kordan region rather than Hablerod region. Though this is a general conclusion, it emphasizes on the necessity of attention to morpho tectonic evidence. It also shows that such studies must be performed in all southern basins of Alborz Mountain and be compared with one another to have better understanding. The ideal research is the outcome of an applicable look on morpho tectonic indexes and morpho tectonic evidences via new methods as well.

Earthquake is one of the natural disasters that due to its unpredictable time and place, causes great financial and life losses. Although earthquakes cannot be prevented, solutions such as zoning and identifying vulnerable regions can greatly mitigate their damages. The purpose of this study is to evaluate the vulnerability of various areas of Urmia City to earthquakes and produce its zoning map. In this regard, the effective factors including building materials, building quality and age, access to passages, slope, population density, number of floor, and proximity to health centers were identified and their relative importance was determined using the method of Analytic Hierarchy Process (AHP). The zoning maps were produced using GIS (Geographic Information Systems), WASPAS (Weighted Aggregated Sum Product Assessment) and WS (Weighted Sum) models. The results of AHP method showed that the building quality and material were more important to regional vulnerability than the other criteria. The calculations required for running the model were carried out in MATLAB. GIS was applied to prepare input and output data and spatial analysis. After producing the final maps, the entire region was investigated in terms of sensitivity and divided into five classes, namely very high risk, high risk, moderate risk, low risk, and very low risk. The results of the WASPAS model shows that an estimated 21% of the entire region has a very high earthquake vulnerability. The comparison of the results obtained from the WASPAS method with WS method showed that in the WASPAS method, more areas have been identified as areas with very high vulnerability.

The main purpose of the current study was to provide a methodological framework for quick and efficient assessment of the vulnerability of urban spaces to earthquake. Most of the variables affecting seismic vulnerability in cities are spatial in nature, so using a geographic information system for integration of these variables can lead to desirable results. However, one of the most important subjects in overlaying of layers in a geographic information system is the uncertainty in weighting and decision making. In this study, attempts were made to modify such uncertainties to a large extent using the functions of catastrophe theory. Using the mentioned approach makes the results of the model repeatable, which is a considerable advantage. Regarding the catastrophe theory, an attempt was made to present the basic equations of this model in a concise and simple way. Varzeqan city was selected for evaluating the seismic vulnerability based on the catastrophe theory. Approximately 21 percent of the total area of Varzeqan lies in the high and very high vulnerability classes. Given that the area of the city's built-up lands is about 32 percent, considerable percentage of these lands in the city is in high and very high vulnerability classes. Distribution of these zones is impressive, especially in the center of the city. These zones can be considered the most critical regions of Varzeqan. Unstable geological formations, high residential and population density, fine grained building, low quality buildings and lack of urban open spaces have caused this region to have severe vulnerability to earthquake.

Modeling wildfire behavior can simplify the understanding of the relationship between fire and its environment, and allow managers to reconstruct or maintain the natural role of fire. In this study, the Minimum Travel Time algorithm in the FlamMap fire model was used to investigate the main pathways of fire growth and the burn probability as a measure of fire risk in the Golestan National Park in northeastern Iran. Based on the simulation output of the main fire pathways in the park, MTT vectors passed through the drier grassland fuels in the southern areas and then split into multiple vectors toward the eastern and northern parts of the park. Using the Chi-square test at the level of P

Environmental issues have great importance in the science of geography and among geographical experts because the foundations this field of science is based on environment. Environmental issues in Iran have grown significantly in recent decades and have overshadowed geographical spaces. The northwestern region of the country has a special situation because the water shortage of Lake Urmia has the potentiality of destroying the existing ecosystem in the future. The present study aimed at identifying the parameters affecting the drying of Lake Urmia and ranking them. The method used in this research is descriptive-analytical method. The data was gathered using questionnaire and library source and the obtained data were analyzed using SPSS software and T-test. The results showed that 44 parameters in human, natural and combined dimensions are involved in the drying of Lake Urmia. Among the human parameters that affect the drying of Lake Urmia, the parameters of disturbing the ecological conditions of the region and lack of attention to water resources management are so important. In natural parameters, change and decrease in rainfall, successive droughts are so important. Moreover, in combined parameters, changing the pattern of cultivation and production of water-rich crops and use of wetlands, regardless of the capacity of wetlands, are the most important factors in the drying of Lake Urmia.

The purpose of this study was to investigate the vulnerability of farmers in the southern Garkan district township facing drought conditions caused by the water crisis of Zayandehrood River. The study tried to answer two questions: 1. how vulnerable are farmers to drought caused by the Zayandehrood water crisis in economic, social and environmental dimensions in the studied villages? 2. What is the level of farmers' awareness of solutions to drought? The statistical population of the study is the farmers of the villages of the Southern Gerkan district, which in 2016 amounted to 2027 person, of which 178 cases were selected as a sample using the Cochran's formula. The validity of the research instrument was confirmed by experts and the reliability of the items with Cronbach's alpha was equal to 0. 85. The required data were collected using a questionnaire and analyzed by statistical tests (Spearman correlation, Chi-square, one-sample t-test and Friedman) and hierarchical analysis technique. The results showed that increasing production costs, increasing psychological stress and falling groundwater levels were respectively as the most important economic, social and environmental damages due to the Zayandehrood water crisis in the region. According to the results of one-sample T-test and Friedman test, socio-psychological injuries have caused the most damage to farmers. A survey of farmers' awareness of drought management methods showed that knowledge of "ways to reduce water loss" is stronger than all other indicators. The results of hierarchical analysis from the perspective of experts showed that the most effective strategy to deal with drought in the region is "irrigation technical solutions".

Monitoring land use and vegetation changes plays an important role in urban management. The purpose of this study was to investigate the changes in vegetation cover of Ahvaz metropolis pertaining to land use changes. First, satellite imagery was prepared through object-oriented vector machine-based algorithm, classified method, and land use maps. To increase the accuracy of the maps, three normalized indices of vegetation difference, soil effect modifier and relative vegetation were used separately in the classification. The results showed that soil effect modifier index had higher capability and its maps with the highest kappa coefficients and overall accuracy were entered into land change modeling to detect changes. Changes in the next 10 years were also predicted using the Markov chain automated cell model. The results of the changes showed that the vegetation has a decreasing trend, so that 1339. 65 hectares the vegetation in the period 1989-1989 and 1860. 50 hectares in the period 2019-2002, have reduced. The most changes are related to the conversion of vegetation into man-made areas with 686. 44 hectares in the period 1989-1989 and 1032. 51 hectares in the period 2019-2002. The least changes are related to the conversion of vegetation into water areas with 7. 18 hectares in the period 1989-2009 and 9. 33 hectares in the period 2019-2002. The results of forecasting changes by 2029 also confirmed the reduction of vegetation. In 10 years, 785. 77 hectares of vegetation will be reduced and the area will reach 2923. 24 hectares.

Urban rivers are of the most important reasons for flood inundation in cities. This study aimed to investigate the morphological effects of the Gorganrood River in Aq’ Qala City in a case of flood inundation on March 2019. The images of Sentinel-2 and Landsat-8 were downloaded for full flood monitoring. After preprocessing, the NDWI and MNDWI indices were applied on the images to extract the flood zones. The sinuosity index and the number and mean radius of meanders were calculated from Sallaq Yilqi village to Dogonchi village using Google Earth and AutoCAD. The NDWI index was appropriate to detect the permanent and clear waters, while the MNDWI index was appropriate to detect the muddy waters and high humidity terrains. The area of flooded zones which obtained from the MNDWI index was 88% more than those of NDWI index. The sinuosity index was 3. 88 (sever meander) in the district of the Sallaq Yilqi village to the Yampi village. Destruction outer arc meanders and low radius of meanders and erosion of soils in upstream were caused overflow the flood in the Gorganrood channel. On the 20th March due to low channel width and very-low gradient of bed river (0. 0002) from the Aq Tekeh Khan village to the Dogonchi village were caused slow velocity of flood stream, therefore the water level was raised and the city of Aq’ Qala were flooded. According to the flood maps obtained, the northern and southern of the Aq’ Qala city located at high-risk zone. Canalization of outer meanders curvature, planting the absorbent vegetation around the quantitative buffer zone of the Gorganrood river, widening and dredging the channel and modifying structure of channel on the northern plains of Gorganrood River can be prevented from flooding over the Aq’ Qala city.

A synoptic perspective was adopted in this study to investigate two winter precipitation systems that caused a flood in Sistan and Baluchestan and a heavy snowfall in Gilan in January 9-12 and February 9-12, 2020, respectively. The results demonstrated that although different in shape, both systems were cold-core and similar in their formation and strengthening. Amplification of the mid-level trough, formation of cyclonic rotation, positive relative vorticity advection to the east of the trough, convergence in lower levels, and formation or strengthening of low-pressure at the Earth’ s surface to the east of the trough, played the key role in developing and strengthening these two systems. These mechanisms are consistent with the theory of development and strengthening of mid-latitude low-pressure systems. A noticeable difference between these two systems is the continuity and increasing speed of the north wind in the first system, caused by the meridional shift in the polar jet stream. These conditions have caused the cyclonic curvature formed in the subtropical jet stream axis in the first system to be increase and extended to the south. These curvatures are located to the east of the Red Sea in the first system and northeast of the Mediterranean Sea in the second system. Also, in the first system, the advection of warm moist air from the Arabian Sea and the Gulf of Oman, and in the second system, the advection of cold air from the Caspian Sea have provided suitable conditions for convectional rainfall and heavy snowfall, respectively.