Showing 4 results for Stability
Tahereh Karimi, Amir Karam, Parviz Zeaiean Firuzabadi, Seyyed Mohammad Tavakkoli Sabour,
Volume 0, Issue 0 (3-1921)
Abstract
Abstract
The catchment area of Alamut River in Qazvin province is witnessing numerous landslide hazards and landslides every year, which cause significant economic and sometimes life-threatening losses. Diagnosing the unstable areas of slopes through soil texture characteristics is a difficult task due to the difficulties of obtaining soil samples in mountainous areas. For this reason, in the present study, by using Sentinel A1 radar data, by determining the percentage of clay and sand in the soil, the soil texture map at the depths of 10, 60, 100 and 200 cm with two random forest (RF) and support vector machine (SVM) algorithms was produced in the eastern Alamut region, which was verified with soil profile samples. The results indicated that the Kappa index was more accurate in the RF model at three depths of 10, 60 and 100 cm. Then, by extracting the soil moisture map from Sentinel 2 data, at the same time as examining the internal friction angle of the types of soils in the region, comparing the slope and profile of the slopes and the shape of the convex (divergent) and concave (convergent) slopes, the unstable areas of slope movements, RF and SVM models were specified and validated with GPS data, field visits and Google Earth. Research findings show that the instability map resulting from the RF model has a higher accuracy (AUC=0.93) than the instability map resulting from the SVM model (AUC=0.90) and there is more instability in areas with medium to high slope and with soil texture of sandy clay loam and sandy loam. . This method has many advantages in preparing the soil texture map, determining the unstable areas of the slopes against mass movements and landslides, determining the vulnerable areas in mountainous areas and reducing financial and human losses.
Sadegh Asghari, Gharib Fazelniya, Morteza Tavakoly, Marzie Shoghi,
Volume 15, Issue 37 (9-2015)
Abstract
Sustainable development is an environmental concept appropriate to our era that nowadays in all of economic, social, environmental and physical-spatial aspects is considered and focused by everyone. In these times, global organizations that are working around the issues of sustainable development, emphasis on rural sustainable development, which seeks to improve rural living standards and welfare of the inhabitants of the villages, because at present time, the procedure of socio–economic variations accompanied by increasing migration of human groups is led to evacuation of villages. With attention to the importance of the subject and the increasing instability of the villages, present study was done for determining the effective factors on rural instability and measuring the intensity of this instability in Kaki District of Dashti Township. The research method is descriptive - analytical in which whole inhabited villages of Kaki District of Dashti Township were surveyed. In this regard, according to the number of households living in villages and using the Cochran formula, 255 questionnaires were calculated for questioning andthese questionnaires have been completed in the villages in proportion to the population of each village. In these questionnaires, 34 indicators related to the four dimensions of sustainable development (environmental, social, economic and physical-spatial) are considered. In order to determining instability intensity of the villages and their spatial analysis, is used AHP method in Expert Choice and ArcGIS software. Also SPSS software is used for statistical analysis. The results show that at the present time, all villages have various degrees of instability. In this regard, 65.8 percent of these villages have severe or very severe instability.
Mohammad Ajza Shokouhi, Shirin Sabaghi Abkooh, Forough Kazaei Nejad,
Volume 21, Issue 62 (10-2021)
Abstract
A new urbanism theory has emerged in recent decades in response to numerous urban problems of the twentieth century, with the goal of creating vibrant, compact, diverse and desirable cities in terms of work, walking, life, and transportation options. In view of the widespread acceptance of this theory among the Iranian researchers, the aim of this study is to assess the sustainability of organic and planned neighborhoods in Mashhad based on the spatial-physical indexes of new urbanism. In this regard, two neighborhoods, RahAhan (organic neighborhood) and the second phase of Rezashahr (planned neighborhood) were selected. This research method is descriptive- analytical and the mixed model of AHP and GIS has been used to assess the stability of two neighborhoods. Accordingly, the Sustainability Measurement Model was used as a hierarchy in the form of 7 physical-space indicators (type of road, pedestrian width, land use, area of lots, access to the center of the neighborhood, number of floors and access to public transport) . Tthe research results show that in Rezashhar, 68.43% of neighborhood area has moderate to high stability and 31.57% of the total of the neighborhood area is the lack of stability, and in RahAhan, 70.84% of the total of the neighborhood has moderate to high stability and 29.16% of the total of the neighborhood is lack of stability. Therefore, according to the spatial indicators of the new urbanism, the neighborhood of Reza Shahr is more unsustainable than the old neighborhood of Rah Ahan. Therefore, this study shows the richness of traditional Iranian urbanization and the superiority of old neighborhoods. So, it can be said that traditional and organic urbanization is a more appropriate basis for applying the new urbanism approach and this approach can be used in the form of urban regeneration.
Ms Akram Hedayati Dezfuli, Ms Zahra Ghassabi,
Volume 24, Issue 73 (8-2024)
Abstract
Flood is one of the most destructive natural phenomena. Every year it brings extensive losses to the country’s financial and human resources. In our country, major parts of Iran’s provinces are always at risk of flooding. The Gorgan and Atrak catchments have also become more important, as several floods have occurred in Golestan province in recent years, causing many deaths and economic losses. The purpose of this study was to investigate the synoptic and thermodynamic conditions of the March 2019 flood event in Golestan province in order to atmospheric system that lead to such floods. This study includes statistical analysis of provincial stations (Gorgan, Gonbadkavus, Aliabadkatol, Hashemabad, Kalale, Maravetape and Bandaretokman), calculating of the return period of precipitation during the available statistical period of each station, analysis of synoptic maps on the day of the flood event, the analysis of satellite images of the days involved in the flood, and calculation of instability indices of the Gorgans’s station. Statistical results showed that Gorgan and Gonbadkavus stations, with the highest amount of rainfall in March 2019, had a return period with 800 and 400 years respectively. Also the highest amount index of Gorgan with values of K=26°c, PW= 0.27 cm and TT= 48 was obtained with high relative humidity (about 80%). The analysis of the synoptic maps showed the severe sea level pressure and mid- level height drop with a deep trough in the study area, which led to extreme rainfall.
Key words: Flood, return period, Synoptic maps, instability indices, Golestan province.
