Remote Sensing (RS)
Mohamad Fathollahzadeh; Mojtaba Yamani; Abolghasem Goorabi; Mehran Maghsoudi; Mernoosh Ghadimi
Abstract
Extended Abstract
Introduction:
The landforms created by tectonic processes are studied by morphotectonics, in other words, morphotectonics is the science of applying geomorphic principles in solving tectonic problems. Quantitative landscape measurements are usually based on the calculation of geomorphic ...
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Extended Abstract
Introduction:
The landforms created by tectonic processes are studied by morphotectonics, in other words, morphotectonics is the science of applying geomorphic principles in solving tectonic problems. Quantitative landscape measurements are usually based on the calculation of geomorphic indices, using topographic maps, satellite images aerial photographs, and field visits. Coastal deltas are part of landforms and landscapes that, due to the proximity of two environments, land, and water, leave visible effects against tectonic activities, such as changing the pattern and location of deltas due to the change in the course of coastal rivers, the formation of unbalanced coastal terraces in parts of the coast, and the emergence of cut beaches in the form of seawalls.
One of the methods of identifying and measuring land changes is using radar remote sensing. The principles of this technique were first described by Graham in 1974 (Pacheco et al., 2006). Interferometry using radar images with an artificial window or SAR is a precise method based on the use of at least two radar images of the same area, which measures the height displacement changes in wide areas and during different time intervals with a significant accuracy of millimeters (Dong et al., 2018).
The coastal areas of northern Iran are of great importance due to the high population density and the ability to grow and develop economically and agriculturally, so monitoring geomorphic changes in the direction of sustainable development of these areas is particularly important.
In this research, the eastern coast of the Caspian Sea from Gomishan to Joibar is investigated in terms of subsidence and uplift using radar remote sensing techniques to determine the active tectonic zones of the coast in terms of temporal and spatial changes.
Materials and Methods:
The Eastern Caspian Plain is the border between the Caspian Sea and West Gorgan and includes the cities of Gomishan, Bandare Turkman, Bandare Gaz, Gulugah, Khazarabad, and Joybar. The absolute height of the Caspian Plain along the coastline is determined according to the sea level, based on the hydrographic data of the Baku station, since 1850, the Caspian sea level has varied between -25.4 and -29.4 (Abdolhi Kakrodi, 2012).
The history of seismic activity in North Alborz shows that cities like Rasht, Lahijan, Amol, and Gorgan, have been destroyed many times due to destructive earthquakes (Aqhanbati, 2013). The Alborz fault is an active fault that is stretched in a clockwise direction in the southern Caspian basin.
In this research, according to the desired goals and radar remote sensing techniques, a series of Sentinel-1 radar images with a suitable time and space difference (maximum 30 days and maximum 150 meters respectively) including 61 images in time from 2014 to 2021 were prepared and processed.
Results:
The results obtained from the SBAS model indicate that the eastern part of the Caspian coast is more affected by the uplift and this trend continues up to Gorgan Bay. The Gorgan city has an uplift between 20 and 40 mm/year, which is reversed towards the coastal area, and subsidence of 10 to 52 mm/year occurs, which decreases as it approaches the coast and reaches 10 mm /year.
Discussion, Conclusion:
According to the results obtained from radar interferometry, the eastern coast of the Caspian Sea is more affected by uplifting. The Gorgan city has an uplift between 20 and 40 mm/year, which is reversed towards the coastal area, and subsidence of 10 to 52 mm/year occurs, which decreases as it approaches the coast and reaches 10 mm/year.
To verify the results obtained, the data of the Gorgan geodynamic station was used, which shows subsidence of about 90 to 100 mm in a 6-year period, which is consistent with the values obtained from radar interferometry Based on comments Shahpasandzadeh (2013) and the reports of Nazari et al (2021), active tectonics caused by the Caspian fault that indicates the horizontal geodynamic displacement diagram of Gorgan, the small area towards the north and east during this time, which is observed in the form of numerous branches with a thrust (reverse) mechanism and a right-slip component with a slope to the south in Golestan province.
Considering that the main feature of the coast of the Caspian Sea is the Surface rivers and the use of groundwater is very little and also the extraction of gas, oil, and mining resources, which is another factor in the occurrence of land subsidence, does not exist in this area, and there isn’t also huge and heavy structure in the study area that affects the subsidence of the surface; so displacement in the study area is the result of active tectonics.
Geographic Data
Mehran Maghsoudi; Mohamad Fathollahzadeh; Hamid Ganjaeian
Abstract
Extended Abstract
Introduction
Surface winds move and transport soil particles on the ground and thus, affect the intensity of erosion to a great degree (Tage Din et al, 1986: 118). Various studies have found a decreasing trend for surface wind speed in different parts of the world in recent years. ...
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Extended Abstract
Introduction
Surface winds move and transport soil particles on the ground and thus, affect the intensity of erosion to a great degree (Tage Din et al, 1986: 118). Various studies have found a decreasing trend for surface wind speed in different parts of the world in recent years. This decrease has been more widely reported in mid-latitudes (McVicar et al, 2008). Continuous drought in consecutive years is one of the factors that can reduce soil moisture and stop the growth of vegetation cover. (Hereher at el, 2009). Iran is located in the arid belt of the world and two thirds of its total area is located in these arid regions (Maghsoudi, 2006). Previous studies have shown that 17 provinces of the country are affected by wind erosion, among which Kerman faces a more severe conditions. Iran has more than 20 relatively large ergs and several small ergs covering an area of approximately 36,000 square kilometers (Mahmoudi, 1991). The present study investigates different characteristics of winds and its effects on morphology and displacement of sand dunes using Sentinel-2 optical and Sentinel_1 radar images.
Materials and Methods
Due to the lack of any synoptic station in the Lut Desert, related data including wind direction and speed were collected from 6 neighboring stations (Bam, Dehsalm, Zabol, Shahdad, Nusratabad and Nehbandan). Then, a wind rose and a sand rose graph were prepared for each station using WR Plot and Sand Rose Graph software. Resultant force vector acting in the displacement of sands and formation of sand dunes was determined. Following an examination of wind characteristics in the study area using Sentinel-2 optical images collected in the 2016 - 2019 reference period, changes of sand dunes and direction of their movements were also analyzed. In order to investigate vertical displacement in the region, radar interference method and SBAS time series have been used. This method only uses pairs of images in which vertical component of the baseline is less than its critical value, and also have a minimum baseline time. 45 Sentinel_1 radar images were used in the present study to measure radar interference.
Results
Recorded data in Dehsalm, Nehbandan, and Nosrat Abad stations indicate that winds blowing in these stations affect the Lut Desert. The prevailing wind recorded in Dehsalm station blows in northwest to southeast direction of the Lut Erg, while in Nehbandan station, the prevailing wind blows in north to south direction of this Erg. The prevailing wind in Nosrat Abad station blows in southeast to northwest direction of this erg. Sand rose graphs show that DPt in Dehsalam station equals 422.6 and in Nehbandan station equals 484.2. Since both DPts are more than 400, wind in this region has a high energy level and is potentially capable of sand displacement. Changes of sand dunes and direction of their movements were analyzed using Sentinel-2 and Sentinel-1 images in 2016-2019 reference period.
Discussion and Conclusion
Hourly wind speed and direction data in Nehbandan, Dehsalam, and Nosratabad stations were investigated in the present study to evaluate their impact on geomorphological changes in the Lut Erg and its sand dunes. Results indicate that the prevailing wind in these stations blows in north, northwest and southeast direction towards the Lut Erg, respectively. Investigating wind speed changes in Nehbandan station shows that during the last 34 years, average monthly wind speed in this station has decreased from 3.7 meters per second in 1986 to about 2.2 meters per second in 2020, which means a 1.5 meters per second decrease has occurred during this period. Apart from wind speed and direction data, Sentinel-2 optical images were also used to monitor changes in sand dunes of the Lut Erg. Results indicate that during the 2017 - 2018 reference period, most changes have occurred in the sand dunes of the northwest and northeast regions and the margins of this erg, while in the 2018 - 2019 reference period, most changes have occurred in the northwest and southeast regions of the Lut Erg. Analysis of satellite images indicates that the direction of wind force vectors is consistent with the direction of sand transport vector. In other words, sand dune changes in the Lut Erg have occurred under the influence of winds blowing in northwest and southeast directions, which is consistent with the direction of the sand transport vector in plots prepared for the three stations (Nehbandan, Dehsalam, and Nusrataba).
In order to validate the results of wind direction and speed analysis and remote sensing of optical images, vertical displacement of the erg surface was measured in 4-year periods using Sentinel_1 radar images and SBAS time series. In general, southern parts of the Lut Erg and especially sand dunes in these parts have experienced an increase in elevation, while the northern parts of Erg have experienced a decrease in elevation. This can be due to erosion and deposition of sediments in the southern regions of the Lut Erg, which is consistent with the sand rose and wind rose graphs prepared for the region .
Mehran Maghsoudi; Hamid Ganjaeian; Lila Garosi; Anvar Moradi
Abstract
Extended abstract
Introduction
Geomorphology tourism or geotourismis one of the areas ofmodern studies in geoscience and tourism studies based on the identification of geomorphosites or special geomorphological sites. Geomorphosites are of new concepts that have entered the tourism literature with ...
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Extended abstract
Introduction
Geomorphology tourism or geotourismis one of the areas ofmodern studies in geoscience and tourism studies based on the identification of geomorphosites or special geomorphological sites. Geomorphosites are of new concepts that have entered the tourism literature with an emphasis on the location of special sites, therefore, it emphasizes on a set of geographical, geological andgeoarchaeology features. They also havescientific, ecological, cultural and economic values simultaneously and are utilized to understand and exploit human tourism. Geosites, which are a branch of geotourismgive rise to sustainable development in that region, due to their unique attractions. This new economy is completed in a network of cultural heritage and natural resources managements. Geosites of the region must be identified and introduced prior to any planning. Geosites in east Kurdistan province are very less known and only some of them have superficially drawn attentions,therefore, it has been tried to evaluate the capabilities of these geosites in this research while introducing them. This area, along with the attractions of geotourism has also sensitivities and limitations that can be severely damaged, if the red lines are violated. In fact, the purpose of this is to introduce Kurdistan geositeswith the aim of becoming more familiar with the capabilities of this geosite, as well as investigating the geotourist problems of the region in order to pay attention to the planning related to the tourism industry that can be economically effective on areas with geosites.
Materials and methods
This is an applied research, and descriptive-analytical method was used to analyze information and data. The final analysis has been carried out based on the results obtained from the evaluation of the values and criteria of geotourism. Survey procedure, field visits and field studiesas well as library and documentary studies have been used to collect information. The combination of library and field information will determine the overall value of the region’s geotourism. Two methods of Comanescu and Fassoulaswere used to evaluate the geosites in this research. In addition to evaluating geosites, the areas susceptible to geotourism development in the study area were zoned, and two Fuzzy and ANP models were used for this purpose. The methodology is in a way that the data layers first became fuzzy and comparable, using fuzzy model. Then, the obtained weight was multiplied by each one of the data layers, and thefinal map was obtained by integrating the data layers in Arc GIS. Finally, geosites which are susceptible to geotourism development were selected using the final results obtained from the zoning as well as the results obtained from the geosites evaluation by the use of two Comanescu and Fassoulasmodels.
Discussion and results
After identifying the geosites, Comanescu and Fassoulas methods were used to evaluate them. For this purpose, library methods and experts’ opinionshavebeenused. First, the geosites were evaluated according to the criteria of Comanescu method, and based on the final results obtained from the evaluations, the GhalehQomchoqayhas the highestvaluewith a totalof 84 scores. After the GharQomchoqay, SarabQorveh and CheshmehTangzhave the highest valueswith 76 and 69 scores, respectively. Then the geosites were evaluated using the Fassoulas method, and according to the final results, GhalehQomchoqay and SarabQorveh with a total of 17.5 and 13 scores have the highest values, respectively. The results obtained from the evaluation by both Comanescu and Fassoulasmethods indicate the high value of GharQomchoqay and SarabQorveh for geotourism purposes. In the present research, in addition to the geosites evaluation, areas susceptible to development have been identified using the intended criteria and two Fuzzy and ANP models have been used for this purpose.
Conclusion
After the evaluation done by the methods of Comanescu and Fassoulas,zoning of the areas susceptible to geotourism development was carried out,using the intended criteria. The results indicate that among the geosites of the study area, 8 geosites including GhalehQomchoqay,SarabQorveh, CheshmehTangz and Baba GoorGoor’sEzhdaha Mount, Badr and Parishan mountains, GharGolestaneh, KoohNesar and SarabBijar have a high Potential for the purposes of geotourism development. In most important of researches done in the country, the evaluation methods have only been used. However, the most important advantage of this research is that all the necessary criteria have been evaluated and the final result has been the outcome of the multi-criteria evaluation. In fact, in addition to the evaluation methods, the zoning methods have also been used. The use of zoning methods has led to taking the environmental factors into consideration in the selection of top sites and the sites selected as sexemplary sites need to meet all the necessary requirements for the development of geotourism infrastructure.
Mehran Maghsoudi; Abdolhosein Hajizadeh; Mohammad Ali Nezam mahaleh; Zeinab Bayati Sedaghat
Abstract
The Lut Desert is in the southeast of Kerman province and one of the largest deserts of the world, which is one of the world’s driest and hottest places.Granulometric analysis of sediments can indicate the characteristics of the old formative processes and the morphology of landforms. Yardangs ...
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The Lut Desert is in the southeast of Kerman province and one of the largest deserts of the world, which is one of the world’s driest and hottest places.Granulometric analysis of sediments can indicate the characteristics of the old formative processes and the morphology of landforms. Yardangs (Kaluts) ofthe Lutplain have a very interesting and unique morphology in Iran and in the world, and recognizing the relationship between their granulometric characteristics and their rough and uneven shape, which is a set of diagonal hills or more or less parallel strands, can provide useful information. In this study, two samples of yardang or kalutfrom the Lut plain in the northeast of Shahdadcity located in north of Kaluts were selected and a number of sediment samples from different heights were taken in accordance with sampling principles. The sediment samples were measured in laboratory using pipette method. This method was first designed and implemented by the authors at the Faculty of Geography in Tehran University. In these two Yardang samples, it was found that water and wind erosion are among the dominant processes forming the Yardang shapes of the North of the Lut plain. In this research,calcimetry test, determination of sediment color was performed, and statistical parameters such as the mean of grains, standard deviation (SD), kurtosis and skewness of data were also calculated. According to the results derived from the granulometry and its related parameters, it can be concluded that the Yardangs of the northern part of the Lut plain at all altitudes of this form of roughness contain mainly muddy deposits. The results have also showna higher amount of silty sediments at higher altitudes of these two Yardangs. This research indicates that, the studied morphology of ovoid yardangs is in relation with the upper part’ssilty sediments and the lower part’s clayey sediments of these forms of roughness. It should be noted that, this article was taken from a research project which was completed through financial support of the Faculty of Geography-University of Tehran.
Mehran Maghsoudi; Bahram Nekouei Sadri
Volume 16, Issue 64 , February 2008, , Pages 61-64
Abstract
Geotourism, as a subcategory of ecotourism, has, along with other tourism areas such as rural, cultural, etc., a potential for employment of a great number of related professionals. This industry can have an effective role in the economic development of the country, which is why tourism industry is considered ...
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Geotourism, as a subcategory of ecotourism, has, along with other tourism areas such as rural, cultural, etc., a potential for employment of a great number of related professionals. This industry can have an effective role in the economic development of the country, which is why tourism industry is considered the most important industry in the world. Of course, the idea of a large number of experts and non-experts concerning tourism industry is merely recreational tourism, which is contrary to the new perspective of the subject in the world. In fact, today in many cases tourists from advanced societies are looking for science, culture, and ecological, geomorphologic and geologic attractions. It is worth noting that this industry is still not well known in Iran and potential capabilities of Iran have not yet been evaluated in this regard. With a variety of geomorphologic and geological structures, Iran has a wide variety in this regard and calls for new grounds in the field of tourism industry in the country. According to the abovementioned matters, the identification and marketing of geotourism and ecotourism phenomena in Iran in order to exploit this great potential is unavoidable. In this article, while studying concepts and dimensions of geotourism, it is tried to discuss some of the geotourist general qualities and attractions of Iran.
Mehran Maghsudi; Hamid Bidi
Volume 16, Issue 62 , August 2007, , Pages 77-79
Abstract
India has a vast coastal area of about 7,500 km long with a vast store of sandy minerals such as ilmenite, rutile, zircon, monazite, silimanite and garnet. The purpose of this study is to provide map of coastal land forms using multi-spectral remote sensing in order to be able to identify areas ...
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India has a vast coastal area of about 7,500 km long with a vast store of sandy minerals such as ilmenite, rutile, zircon, monazite, silimanite and garnet. The purpose of this study is to provide map of coastal land forms using multi-spectral remote sensing in order to be able to identify areas suitable for land surveys carried out with the aim of discovering alluvial minerals.
Generally, surface substances are the result of the interaction of three different variables:
1. The nature of sub-surface rocks;
2. The internal movements of the Earth, called tectonic regimes;
3. Active external processes, mainly controlled by the factor of climate.
Therefore, an accurate geomorphological study of formation of alluvial minerals in all scales seems necessary. (Rajamanickam, 1997/ Sutherland et al., 1985) Coastal areas have special advantages for the exploration of coastal alluvial minerals.
India has a vast coastal area of about 7,500 km long with a vast store of sandy minerals such as ilmenite, rutile, zircon, monazite, silimanite and garnet. Most of these sediments, with the exception of some alluvial deposits on land and sands, are mainly located in the coastal strip of the Indian subcontinent. The Tamil Nadu coastline is about 975 kilometers, 915 kilometers of which are on the east coast and 60 kilometers off the west coast of India. Detailed (60 km) and preliminary (519 km) surveys were carried out on 579 km of coastal length. However, 396 kilometers still have to be surveyed.
Investigations on sediments containing heavy minerals in the hills and sandy beaches by close grid sample on 508 kilometers of coastal length indicate high concentrations of heavy minerals from surface to depths of several meters. (Mohanand Rajamanickam, 2000)
Mehran Maghsudi; Sepideh Zandieh
Volume 16, Issue 61 , May 2007, , Pages 35-38
Abstract
Today, almost all reports, scholarly research and applied projects that somehow deal with the dispersion of geographic phenomena use thematic maps. In the European countries production of thematic maps go back to the 17th century, but in our country, the preparation of these maps began with the compilation ...
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Today, almost all reports, scholarly research and applied projects that somehow deal with the dispersion of geographic phenomena use thematic maps. In the European countries production of thematic maps go back to the 17th century, but in our country, the preparation of these maps began with the compilation of atlases by some organizations in the 1960s. A special type of thematic maps which has been widely used, is the choropleth map. Choropleth maps are used to display the distribution of quantitative phenomena over a political or administrative area such as province, city, district and rural districts. Choropleth maps are usually represented by graduated color or hachures. An important point in the development of choropleth maps is to find the appropriate classification system for the data utilized. In fact, there are various classification systems in this regard that may be confused by users if a proper classification system is not selected for information display. In this research, we tried to study the classification methods in choropleth maps and specify the characteristics of each of them.
