Journal of Spatial Analysis Environmental Hazards

Analyzing the trend of deforestation using Support Vector Machine (SVM) and Maximum Likelihood Classification (MLC) models and its effect on land surface temperature (LST) and spectral indices (study area: Talesh forest area)

arastoo yari

Earth surface temperature provides important information on the role of land use and land cover on energy balance processes. Therefore, the purpose of this research is to evaluate the LST patterns due to changes in land use (LULC). The studied area is located in Talesh region with an area of 300.6 square kilometers. For this purpose, Landsat images were downloaded in dry and wet seasons from 1365 to 1401. Four user classes were identified by maximum likelihood classification (MLC) and support vector machine (SVM) in 36-year intervals. The Kappa coefficient values for the SVM model were equal to 0.7802 and for the MLC model it was equal to 0.5328. NDVI, NDSI, and NDWI spectral indices were calculated for vegetation, barren soil, and water and were compared with LST in the above years. Changes in land use during the years 1365 to 1401 were an important factor in changes in the temperature of the earth's surface, which averaged from 13.7 degrees Celsius to 39.5 degrees Celsius in the wet season and -0.37 to 41.07 degrees Celsius in the dry season has been variable. Water areas and vegetation have the lowest and barren soil have the highest LST values. The highest negative correlation of -0.74 belongs to the NDVI index in 1365 and the highest positive correlation of 0.79 belongs to the NDSI index in 1365. The area of the forest area has decreased by 20.3% and agricultural land has increased by 217% in 36 years. Barren lands have changed the most and decreased from 2.68 square kilometers to 12 square kilometers. In general, LST has increased due to the increase of human activities such as the expansion of agricultural land and deforestation in the studied period.

Systematic review of flood resilience assessment approaches and methods in urban environments

Majid Ramezani Mehrian

Population growth and urbanization are two primary factors in increasing the risk of flooding in urban areas. Along with the increasing urbanization in many cities, changes in land use have led to an increase in the volume of surface runoff and a change in the flood regimes of rivers. Therefore, urban flooding is one of the risks that directly and indirectly have harmful effects. It has entered various cities in Iran. Since resilience thought provides a comprehensive understanding of the conditions by combining different components, it can be fruitful in creating urban flood risk management tools. To be able to effectively use the concept of resilience in the process of decision-making and management of urban floods, it is necessary to measure and evaluate the city's resilience against flood risk. Despite this, the measurement of resilience in urban environments against floods faces a serious challenge due to the lack of transparency in the field of methodological approaches. Therefore, this study aims to clarify the approaches and methods with a systematic review and meta-analysis of the studies conducted in the field of assessing the resilience of urban environments against floods. According to the findings of the research, the methods of assessing the resilience of urban environments against floods are divided into three categories: quantitative, semi-quantitative, and qualitative. Qualitative methods have less diversity than quantitative methods and often include interviewing methods and theoretical conceptual frameworks. The majority of evaluation methods in this field are quantitative and semi-quantitative methods, which can be placed in two widely used categories, i.e. simulation-based methods and indexing-based methods. In the simulation-based approach, hydrological modeling and flood simulation are generally used. Methods based on indexing have been developed in different ways, but they generally follow the same principles and can be used to analyze the resilience of other types of risks in geographic areas.

Measuring the economic resilience of new urban Habitations against Risk of earthquakes using EDAS Method (Case Study: Isfahan Metropolitan)

Ali zangiabadi

Economic resilience to natural disasters, which is actually how economic capacities affect disasters, is one of the issues that must be considered in any society. It is noteworthy that the type of attitude towards economic resilience and how to analyze it on the one hand, plays a key role in how to recognize the current situation resilience and its causes, and on the other hand also affects policies and measures to reduce risk and how to deal with it. The purpose of this study is to rank the economic resilience of new urban Habitations in the Isfahan Metropolitan against earthquake risk. Due to the studied components and the nature of the subject, the approach of this research is "descriptive-analytical". The statistical population of this study includes 6 new urban Habitations of Shahin shahr, Majlesi, Sepahan shahr, Fooladshahr, Baharestan and Shahid Keshvari. This research is applied in terms of purpose and in the research literature section, information has been collected through the library method. According to the results obtained from ASI in this study, the new urban Habitations of Baharestan, Majlesi, Fooladshahr, Shahid Keshvari, Sepahan Shahr and Shahin Shahr have the first to sixth ranks in terms of economic resilience to earthquake risk, respectively. In order to reduce the adverse effects of earthquake risk, pay attention to the economic capacity of the studied Habitations and reduce the economic risk factors in each community, economic resilience should be considered to avoid financial losses caused by these possible accidents.

Analysis of the role of urban green infrastructure changes in the ecological resilience of District 1 of Tehran Municipality

Tajdin Karami

Abstract
Ecological resilience is a concept that implies the reversibility of ecological structures and functions against the shocks experienced. The northern zone of Tehran, as the most important ecological support of this city, has undergone many land-use changes in recent decades. The present study has analyzed the role of land-use change in the ecological resilience of green infrastructure (as one of the pillars of ecological structure) in District 1 of Tehran Municipality. This study is an applied one in terms of purpose and is considered a descriptive-analytical one in terms of the method used. In this study Landsat satellite data (1976-2021) were used to detect the changes of interest, and landscape metrics were used to analyze the ecological resilience conditions. Based on the results of this study period, the Number of Patches (NP) has significantly increased and the Class Area (CA) has decreased during the period covered by this study. These changes indicate the fragmentation process and loss of structural cohesion of the green patches. The measurement results for the connectivity metrics (ENN and GYRATE) also showed a small connectivity between the green patches in the area. In addition, the results for CONTAG (Contagion Landscape metrics) measure indicated that, due to low connectivity, the transmission rate is low. Therefore, it can be said that the green infrastructure of the region has lost its structural cohesion in the face of land-use change, and as a result, the expected ecological functions and services have also failed. According to the results, the green infrastructure of the study area is vulnerable to land-use changes and their ecological resilience has been significantly reduced.

Evaluation of morphotectonic indicators based on the focus of earthquakes and the function of faults in Iran

Hassan jafari

Abstract
In geosciences, morphotectonic indicators are used to investigate the effectiveness of land surfaces from neotectonic activities. In this article, the results of morphotectonic indices by tectonic zones of Iran, according to the energy released from the earthquake of 1900-2009 and the position of the basins relative to the types of faults (young seismic faults), Quaternary and pre-Quaternary) were analyzed. For this purpose, 110 years old Iran seismic data was extracted from the geodatabase, and during the programming process in MATLAB, it was converted from point-vector to surface-raster. In addition the results of the evaluation of morphotectonic indices of 142 basins of different zones were used; 8 inactive basins, 40 semi- active basins, and 94 active basins. Inactive basins are located in Alborz, Zagros, and Central Iran. . The results indicate that the amount of energy released can't examine a significant role in evaluating the morphotectonic indices of the basins. Basin’s location in the area of Quaternary faults and young seismic is of great value in the tectonically active basin. The lie of semi-active basins adjacent to active basins, or the lie of inactive basins adjacent to semi-active and active basins; and it should be borne in mind that the thresholds used to estimate the tectonic activity status of basins cannot be used as a definite and mathematical criterion in estimating the tectonic status of basins.

Evaluation of soil carbon accumulation potential of Capparis decidua and Prosopis cineraria species (Case study: Keshtegan, Saravan)

Mohammad Reza Rigi

Introduction: Nowadays, climate change and global warming caused by increasing concentrations of greenhouse gases, especially carbon dioxide, is one of the major challenges facing sustainable development. Carbon accumulation in plant biomass and soils is the simplest and economically way to reduce levels of this atmospheric gas. No research has been done on the assessment of the potential of soil carbon deposition and accumulation in the Capparis decidua and Prosopis cineraria species.
Data and Methodology: The objective of this study was to evaluate the soil carbon accumulation in Capparis decidua and Prosopis cineraria plant species in Keshtegan of Saravan, Iran. Therefore, in order to determine the amount of carbon stored in the soil, soil sampling was done by random-systematic method. One hundered-meter transects were randomly selected in the study areas and sampling points were dug at similar intervals along the transect for sampling.Soil samples were taken from depth of 0 to 30 centimeters under the canopy of Capparis decidua and Prosopis cineraria and bare soil as control (20 samples from each area). Soil organic carbon, soil bulk density, pH, salinity and content of clay, silt and sand were recorded.
Description and Interpretation of Results: The analysis of the data showed that there is a significant difference between the investigated treatments in terms of the amount of clay, organic carbon and carbon accumulation. The average comparison results showed that there is a significant difference between the soil covered by plant species and the soil of the control area. The amount of soil carbon accumulated in the area covered by Capparis decidua (1.32 tons per hectare) was significantly higher than that in area covered by Prosopis cineraria (0.75 tons per hectare) and the control area (0.25 tons per hectare). It shows the positive effect of two plant species on the amount of soil carbon accumulation. The average amount of organic carbon in the area with the Capparis decidua, Prosopis cineraria and the control area was 0.75, 0.31 and 0.1 tons per hectare, respectively.Soil organic matter and sand percentage under the canopy of both plant species were higher than the control. In terms of other characteristics, no significant difference was observed in the three regions. According to the results, it can be stated that the presence of plant canopy can increases the amount of carbon accumulation in the soil and led to global warming mitigation.

Investigation of natural and human hazards and vulnerability of historical fabric in Ferdowsi neighborhood of Tehran

Habibollah Fasihi

Urban planners consider historical fabric as the beating heart of cities. However, cities and specifically their historical fabrics are constantly under influence of natural and human-induced hazards. This study aimed to assess the vulnerability of Ferdowsi neighborhood as an example of Tehran’s historical fabric. The data was obtained from geographical information system (GIS) files and a survey, as well as historical contexts and documents were analyzed as part of this study. Ten municipal experts were also asked to provide a score of 1 to 5 for each of the 29 indicators compared to standard levels. The mean value of these scores was then used to evaluate the role of each parameter in the vulnerability of this neighborhood. Study findings indicate a high potential for the occurrence of natural and human-induced hazards in the study area. The abundance of unstable multistory buildings and derelict electricity and water networks, storage of flammables in warehouses, and lack of sewage network for half of the buildings were the most significant factors contributing to the vulnerability of this ancient fabric. Problems such as insecurity, drug abuse in public spaces, overcrowding and daytime congestion have also led to rapid relocation of neighborhood residents, who subsequently were replaced by commercial activities and warehouses. In conclusion, numerous problems are contributing to the vulnerability of historical fabric of this neighborhood and such problems are highly likely to be applied to other urban historical fabrics in Tehran.

Understanding the mechanism of the atmospheric anomalies governing the summer dust in northeast Iran

Tahmineh chehreara

Identification of dust centers and, of course, the behavior of this phenomenon in different regions creates one of the problems of the last few decades, which is investigated as a hazard. To this end, statistics from 15 meteorological stations in the northeastern region of Iran, including North Khorasan, Razavi Khorasan, and South Khorasan provinces, were used over a 17-year period (2016-2000). To clarify the mechanisms governing dusty days, the meridional and zonal wind components and geopotential height were obtained by referring to the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR). HYSPLIT model and MODIS AOD values were used to track and identify dust centers. The results showed that during the warm season, due to the establishment of a strong quasi-stationary blocking system in the lower levels of the atmosphere, negative vorticity increased in the maximum air descent area, ultimately leading to the dominance of a northern flow for the region. Anomalies in geopotential height and vorticity were identified, and three dominant abnormal patterns were found in the occurrence of maximum dust storms in the region. An increase in geopotential height of more than 5 to 10 geopotential meters and an increase in negative vorticity are considered major conditions. By examining the tracking model and using satellite data, five main centers that affect over 90% of the region's dust storms were identified, among which Turkmenistan has a significant role with two separate centers and one common center with Uzbekistan in the occurrence of summer dust storms in northeastern Iran.

Studying the threats and vulnerability of geosites in the north of Garmsar and Aradan region for the purpose of protection

mehran maghsoudi

Geological diversity has created a new branch of the tourism industry called geotourism , where geological and geomorphological features are explored . The main focus of geotourism on geological elements includes two items, form and process . There is a set of geological forms and processes in places , which are called geosites . This has given rise to a new branch of tourism called geotourism , which examines places that have the ability to attract tourists and management aspects that can help the local community for economic development. In the first stage , it is very important to know the abilities and characteristics of the studied area . Scientific, tourism and educational evaluation of geosites in the region is the basis for optimal exploitation and sustainable development. In recent years, more attention has been paid to the Garmsar region, which has led to the development of geotourism. The impact of tourists and mines that have been created by humans, the Tastkan caves that have changed the strength of the salt caves, and also the role of natural factors, have all led to the environment's reaction

Temporal-spatial monitoring of the Namak Lake playa changes and its environmental impacts on the surrounding regions

Sara KIANI

The Namak Lake is situated between three provinces: Isfahan, Qom, and Semnan. However, the functioning of Namak Lake and its susceptibility to environmental, ecological, economic, and social influences not only affect the immediate surroundings but also impact other provinces. Naturally, a crisis in this lake can have negative effects on human communities and the residents of the surrounding areas in terms of environmental, economic, and social aspects. Therefore, the aim of this research is to identify the temporal-spatial changes in the salinity of Namak Lake and, subsequently, to investigate and analyze the effects of these changes on the environmental security of the surrounding regions. To achieve this goal, salt zones were identified using soil salinity indices, including the Normalized Difference Salinity Index (NDSI), Salinity Index 1 (SI1), Salinity Index 2 (SI2), and Brightness Index (BI), over a 30-year period (1992-2021) with five-year intervals. Then, using the maximum likelihood method, the salt zones were classified into four land cover types, including water zone, moist zone, salt zone, and other uses. The results of this study indicate that due to the reduction in water inflow into the lake as a result of dam construction in the upstream basin and the effects of climate change, the water zone, or seasonal lake, of Namak Lake has disappeared and the salt zone has expanded in this area. The most significant changes in the lake are related to the northwestern part of the lake, where major rivers such as Jajrood, Shur, Qarechai, and Qamaroud flow into this part of the lake, contributing to its drainage. Therefore, dam construction on these rivers has led to a downward trend in water flow into the lake. Furthermore, the results suggest that due to the absence of settlements and human communities near Namak Lake and the natural and climatic conditions of the region, it is not expected that environmental incidents that could have security and political implications will occur in the short term.

A qualitative investigation of the effect of natural hazards on industrial plants (with emphasis on oil and gas industries) and Iran's position in this field

mahdi sharifi

By increasing the number of process industrial plants because of societies necessity to their productions, a new branch of accidents caused by various occurred process failures and their effect on the societies and environment and economy has been introduced. Beside it, the increase of the accidents because of natural hazards effect on the industrial plants and their huge costs to the societies and governments and high vulnerability of plants and urbanized territory to the branch of the accidents, increased the attention to this type of accidents. However, in many parts of the world still do not pay attention seriously to this issue and by considering them as very low probability accidents, eliminate paying attention and accepting the responsibility of them while the frequency of such accidents is under growing! In this article according to the existing statistics, an evaluation and comparison of consequences of natural hazards that caused NaTech events has been done. The purpose of the NaTech events is process events that triggered because of natural hazards that are known as events with low probability and high consequences that can affect a wide area and cause huge accidents associated with domino effects. After introducing and categorizing NaTech events, a comparison of their distribution and consequences of these events in Iran and the world has been done according existing articles and researches. Researches shows opposite of the natural hazards and their effects on some structures and infrastructures, Natech events has not been paid under attention enough in Iran. While the variety of industrial plants and their structures in Iran is high, their existing condition and repairing and maintenance of them is not proper and according collected statistics in this article, the potential of NaTech events is also high in country. In the first step, to increase the preparedness for NaTech events, review of effective world experiences in this field is recommended. Recognition of past events and categorizing them and codification of data that should be included in safety reports and scenarios evaluation and considering the domino effects and review the recommendations in this field are parts of this step.

Assessment of desertification Severity in Morad Abad - Saravan Plain using Albedo-NDVI model

Farhad Zolfaghari

Investigation and monitoring of desertification in arid and semi-arid regions is a major concern for societies and governments due to its increasing rate. It is essential to identify areas at risk of desertification to manage and control this phenomenon in the shortest possible time and at minimum cost. The objective of this study is to create a map of desertification intensity in the MoradAbad plain of Saravan using the Albedo-NDVI model, which is based on remote sensing. Two Albedo and NDVI indicators were extracted from Landsat 8 satellite images in Erdas Imaging software after necessary corrections. A linear regression was formed between the two indicators by selecting 200 pixels corresponding to each indicator. Based on the slope coefficient of the line obtained from linear regression, the equation for determining the intensity of desertification was obtained. A map of the intensity of desertification was prepared based on Jenks’ natural refractive index. To evaluate the accuracy of the model, a clutter matrix was formed between 100 corresponding points. The results of linear regression between NDVI and Albedo indices showed that these two indices have a high negative correlation with each other (R = -0.85). The results of the desertification severity classification based on this model showed that 35% of the area is in the very severe class and only 5% of the area is without degradation. The model’s accuracy value was obtained with a kappa coefficient equal to 0.58, indicating good accuracy of the model.