Geological Environment and Engineering
razieh Lak; Ali Mohammadi; Javad Darvishikhatooni; Elnaz Aghaali
Abstract
Heavy rain falls in dray seasons with extreme water flow is one of the important factors in very intense damage urban areas and agricultural lands of the of arid and semi-arid plateaus and highlands. In semi-arid area such as southern flank of Alborz Mountain, neglecting the effect of geomorphologic ...
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Heavy rain falls in dray seasons with extreme water flow is one of the important factors in very intense damage urban areas and agricultural lands of the of arid and semi-arid plateaus and highlands. In semi-arid area such as southern flank of Alborz Mountain, neglecting the effect of geomorphologic features, (e.g. river truck channel depth, slope, sinuosity, river flood plain width and slope), illegal construction on the river legal boundary, as well as the effect of present-day climate change (change in annual rainfall precipitation and patterns, especially in El Niño conditions), cause environmental hazards such as extreme floods in urban areas. Imamzadeh Davood village is a religious-tourist place in the central the Alborz In this research, we investigated the 28th July, 2022 Imamzadeh Davood flood controlling factors and its effect on low-stream village (Imamzadeh Davood) and provided scientific solutions to decrees and prevent the destructive effect of future potential floods. The unusual extreme flood occurred after heavy and sudden rain in July (usually the area receives almost 0 cm of precipitation), causing a large volume of high-density mud flow with highly destructive power in the upper catchment.
Geological Environment and Engineering
Shahrzad Faryadi; Ali Alavi Naeini
Abstract
climate change is known as one of the most important environmental crises which has made many problems . Considering the undeniable impact of humans in the production of greenhouse gasses, in this paper the situation of the climate change of Tehran is predicted by modeling three different scenarios, ...
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climate change is known as one of the most important environmental crises which has made many problems . Considering the undeniable impact of humans in the production of greenhouse gasses, in this paper the situation of the climate change of Tehran is predicted by modeling three different scenarios, for the period of 2046 until 2065. Based on optimistic, pessimistic and neither pessimistic nor optimistic scenarios, the alterations of climate parameters are forecasted. It is concluded that the amount rainfall will decrease, while, the amount of temperature will go up. To do this research the software of LARS-WG is used for modeling the climate change. This software is a sample of Meteorological generating models which is useful for simulation of climate data for now or future in an area. Then, considering the significant role of fossil fuels in deteriorating this phenomenon and determining the proportion of the effects of different modes of transportation in generating carbon, the existing policies on reduction of burning fossil fuels is investigated. At the end, based on the necessity of cooperation of people in various aspects of formulation of policies including behavioral-social and technological-technical, some suggestions are proposed to decrease the production of carbon.
Remote Sensing
N. Namazi; M. R. Jafari; A. R. Jafari Rad; A. Khakzad
Volume 29, Issue 113 , November 2019, , Pages 221-228
Abstract
The study area (Pasghaleh) is located North of Tehran and is part of the Central Alborz Mountain Range. Pasghaleh deposit between coordinates 51º 25´15 ̎ up to 51º 25´ 54̎ Eastern longitude and 35º 49´42 ̎ up to 35º 50´15 ̎ Northern latitude in North ...
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The study area (Pasghaleh) is located North of Tehran and is part of the Central Alborz Mountain Range. Pasghaleh deposit between coordinates 51º 25´15 ̎ up to 51º 25´ 54̎ Eastern longitude and 35º 49´42 ̎ up to 35º 50´15 ̎ Northern latitude in North of Tehran, in the geological sheet with a scale of 1:100000 Tehran and is located East of the Pasghaleh village. Intrusive bodies in this area with age after the Eocene in penetrating Eocene volcanic and pyroclastic units and have altered these units. For mapping minerals and explore the alteration patterns together with Polymetal mineralization in the metallogenic zone Pasghaleh, for sine satellite ASTER and ETM spectral processing and interpretation. According to remote sensing data, it leads to the appearance of Kaolinite and Montmorillonite minerals (Argillic alteration index), Chlorite, Epidote and Calcite (Propylitic alteration index), Muscovite (Sericite alteration index) and Gossan in the range studied. Major mineralization in the region in acid Tuffs altered and scattered. The lithology of this region including pyroclastic rocks of Karaj Formation with Eocene age. Sulfuric minerals observed Pyrite, Chalcopyrite, Sphalerite and Galena. In the whole region Pyrite expands but Lead mineralization, Zinc, Copper, Gold and Silver which process is parallel to the general layering of classes Tuff Silica altered- Feldspathic- Pyrite slightly observed. Pyrite form syngenetic among the Tuffs.Tuffs in formation stage and in the stage of diagenesis, the alteration process Sericitic, Kaolinite and or Chlorite have tolerated. In terms of construction, altered zone mineralize Pasghaleh as a lens and layers plate form between rock units Dacite, Rhyodacite are formed. Based on the study of remote sensing data, presence of alterations Sericite, Argillic and Propylitic (the presence of Chlorite and Epidote) proven in the region, consequently by putting together these alterations to one another, it can be attributed to the alteration pattern of Kuroko Massive sulfide deposits.
M Norouzi; M. Lotfi; M. H. Emami; H. Jamali; A. Abedini
Abstract
Mesgarabad area is located in ~10 km southeast of Tehran, the Central- Alborz structural zone (CASZ) of Iran. The rock units exposed in the area consist of Eocene volcanics, volcano-sedimentary and sedimentary rocks intruded by post upper Eocene granodiorite to quartz monzo-diorite. These subvolcanic ...
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Mesgarabad area is located in ~10 km southeast of Tehran, the Central- Alborz structural zone (CASZ) of Iran. The rock units exposed in the area consist of Eocene volcanics, volcano-sedimentary and sedimentary rocks intruded by post upper Eocene granodiorite to quartz monzo-diorite. These subvolcanic intrusive bodies show porphyroid to microgranular textures and have calc-alkaline magmatic nature. These bodies produced hydrothermal fluids causing extensive alteration zones developed along the Se-Darreh-e-Bozorg strike-slip fault. The effects of hydrothermal fluids on the entire Eocene rock units and subvolcanic intrusive bodies are remarkable. The main alterations are silicification, sericitization, chloritization, epidotizaton, actinolitization, argillization, carbonatization, and alunitization-jarositization, which provided suitable physico-chemical conditions for ore-mineralization. The penetration of subvolcanic intrusive bodies into the Eocene volcanics, volcano-sedimentary and sedimentary rocks brought about skarn mineralization and epithermal barite veins. Microscopic studies and advanced analysis showed that the principal mineral phases in the epithermal zones are magnetite, pyrite, chalcopyrite, bornite, chalcocite, barite, Cu+Sn+Fe alloy, hematite, psilomelane, jacobsite, martite, geothite, and lepidochrosite. The skarnification processes occurred at two distinct stages, (1) progressive and (2) retrogressive. The pyrometasomatic anhydrous minerals such as andradite-grossularite formed during progressive stage and the hydrous minerals like epidote, chlorite, tremolite- actinolite, calcite, quartz, pyrite, chalcopyrite and chalcocite were developed during retrogressive stage. Fluid inclusion studies on primary aqueous inclusions trapped in barite crystals revealed fluid that mixing of two fluids having different physico-chemical conditions played an important role for ore deposition.
H Nazari
Abstract
Many attempts have been done to prepare active faults map of the greater Tehran region, in order to evaluate of probabilistic seismic hazard of the region. Insufficient data about the depth and nature of seismic layer, lack of enough numerical information about the crustal deformation rate, and little ...
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Many attempts have been done to prepare active faults map of the greater Tehran region, in order to evaluate of probabilistic seismic hazard of the region. Insufficient data about the depth and nature of seismic layer, lack of enough numerical information about the crustal deformation rate, and little knowledge about the background seismicity and characteristics of seismic sources, such as seismogenic faults, magnitudes and occurrence interval act as barriers to achieve this evaluation perfectly. In this paper, based on the numerous researches done in seismology, geodynamic and paleoseismology during the last decade, attempt has been done to provide statistical analysis on the basis of paleoseismological studies on major faults of the region such as Astaneh, Firouzkuh, Mosha, Taleghan, North Tehran, Pishva and North Rey as well as the Kahrizak scarps. It is worth to mention that reactivation of any of the mentioned faults could be assigned to the Tehran earthquake, certainly with completely different size affects. According to basis of the extensive paleoseismological data together with morphotectonic investigations in the Central Alborz, the occurrence of a 6.5-7.2 magnitude earthquake during the next 50 years, in the vicinity of Tehran might be probable.
F. Askari; H. Garivani
Abstract
Tehran is the largest and the most populous city of Iran that have been recently regarded from the risk management point of view because of possibility of the earthquake damages. An important destructive phenomenon that may happen in Tehran during an earthquake is liquefaction. In the last ...
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Tehran is the largest and the most populous city of Iran that have been recently regarded from the risk management point of view because of possibility of the earthquake damages. An important destructive phenomenon that may happen in Tehran during an earthquake is liquefaction. In the last two decades, liquefaction of Tehran, especially its southern part, has been extensively studied. These studies are done in different scales and also with different methods. The goal of this paper is consideration of the most important studies which have been done in Tehran up to now and present a practical conclusion. The above mentioned studies are reviewed in the first part of the paper. After that, a network, divided into squares of 1Km×1Km, has been considered in southern part of the Tehran and liquefaction potential for every square of the network is evaluated. Finally, liquefaction hazard map for this part of the city is presented.
H. Nazari; J-F. Ritz; R. Salamati; M. Ghorashi; A. Ghasemi; H. Habibi; F. Jamali; Sh. Javadipur
Abstract
Tehran and its surrounding region are within affecting zone of some active faults of North Tehran and Mosha in north-north east and Parchin and Pishva in south. In addition, there are some other shorter faults and linear markers within the urban area of Tehran such as Niavaran, Mahmoudieh and Davoudieh ...
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Tehran and its surrounding region are within affecting zone of some active faults of North Tehran and Mosha in north-north east and Parchin and Pishva in south. In addition, there are some other shorter faults and linear markers within the urban area of Tehran such as Niavaran, Mahmoudieh and Davoudieh faults in the northern part of city, and Rey and Kahrizak scarps in the south.
Previously, according to occurrence of several historical earthquakes in Rey area and also some geomorphologic evidences, most of these markers with the linear scarps in south Tehran alluviums were mentioned as active faults.
From seismotectonic and urban geology point of view whether these faults exist or not are an important issue. Recent seismotectonic studies including paleoseismology and geophysics investigations have failed to prove existence of such faults beneath the observed surface scarps. So in this paper according to delivered data from our paleoseismology, geophysical and seismotectonic investigations and also some geological evidences of foreland basin deposits (late Quaternary) in the Central Alborz (ex: shoreline evidences in Parchin area-south east of Tehran) and in some other place such Kordan fan (west of Karadj), we suggest that these scarps may be a kind of shoreline in front of the Tehran piedmont or the actual faults may be in different place than that suggested by observation of surface escarps.
In this research we use satellite imagery (Land Sat, Spot, Quick birds), aerial photos and GPS kinematics to do Digital Elevation Model (DEM) through the Kahrizak scarp with paleoseismology trenching and geophysical (Geoelectric and Georadar) investigations on different parts of Rey and Kahrizak scarps.
H. Ghasemi; E. Zabihi; A. Roshandel Kahoo; M. Zare
Abstract
Strong motion records from the 2002 Bam Earthquake are used to investigate the shape of attenuation function in several frequencies ranging between 0.8 to 18 Hz. Amplitude spectra of the records are inverted to find source scaling factor and attenuation parameters using Singular Value Decomposition ...
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Strong motion records from the 2002 Bam Earthquake are used to investigate the shape of attenuation function in several frequencies ranging between 0.8 to 18 Hz. Amplitude spectra of the records are inverted to find source scaling factor and attenuation parameters using Singular Value Decomposition method (SVD). After correcting the obtained attenuation functions for geometrical spreading effect, the values of follow the frequency dependent relation, , which is in good agreement with similar results in other tectonically active regions in the world and could be served as a basic input parameter for future seismic hazard studies in the region of bam.
