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161.
Shafiee Ali Kamalian Mohsen Jafari Mohammad Kazem Hamzehloo Hossein 《Natural Hazards》2011,59(1):481-505
An important step in effectively reducing seismic risk and the vulnerability of a city located in an earthquake prone area
is to conduct a ground motion microzonation study for the desired return period. The International Institute of Earthquake
Engineering and Seismology (IIEES) initiated a number of seismic microzonation projects for Iran. This paper presents the
steps followed by IIEES in ground motion microzonation. IIEES performs both probabilistic and deterministic seismic hazard
analysis. IIEES uses his own fault map for seismotectonic studies and develops modulus and damping curves for the soils in
the study area. The experience of ground motion microzonation shows that in almost all cases, the estimated 475-year peak
ground acceleration (PGA) values are higher than the PGA proposed by the Iranian seismic code. Although ground motion microzonation
in Iran has some shortcomings, IIEES is making new improvement. This includes development in deterministic seismic hazard
analysis, two-dimensional and three-dimensional modelling of basin and topographical effects, using microtremor measurements
to find shear-wave velocity profiles in high-density urban areas and providing maps for spectral acceleration in the study
area. 相似文献
162.
Mohsen Hamidpour Mahmoud Kalbasi Majid Afyuni Hossein Shariatmadari Gerhard Furrer 《Environmental Earth Sciences》2011,62(3):559-568
This study deals with the use of the natural, low-cost sorbents bentonite and zeolite for the removal of lead from aqueous
solutions. The mineral material is from large deposits of bentonite and zeolite that have been discovered recently in Iran.
Experimental and modeling data from our kinetic and equilibrium investigations reveal that (1) the pseudo-second-order kinetic
model gave the best fit, and (2) the Koble–Corrigan sorption model describes the interaction between Pb(II) and the two mineral
materials better than the Freundlich and Langmuir models. However, the sorption of Pb(II) ions by zeolite and bentonite is
complex and probably involves several mechanisms. The experimental data show that natural zeolite and bentonite used in this
study exhibited a reasonable sorption capacity for Pb(II), and thus may be useful for the immobilization of Pb(II) from polluted
sites. 相似文献
163.
Kalaee Mohammad Javad Memarian Mohammad Hossein Nekoie Zahra 《Geomagnetism and Aeronomy》2021,61(8):1240-1250
Geomagnetism and Aeronomy - The global TEC (Total Electron Content) behavior has been studied for several decades, but some properties of this behavior have not been understood well, such as the... 相似文献
164.
Recent trends of mean maximum and minimum air temperatures in the western half of Iran 总被引:3,自引:0,他引:3
Hossein Tabari Parisa Hosseinzadeh Talaee 《Meteorology and Atmospheric Physics》2011,111(3-4):121-131
In this study, the trends of the annual, seasonal and monthly maximum (T max) and minimum (T min) air temperatures time series were investigated for 20 stations in the western half of Iran during 1966?C2005. Three statistical tests including Mann?CKendall, Sen??s slope estimator and linear regression were used for the analysis. The annual T max and T min series showed a positive trend in 85% of the stations and a negative trend in 15% of the stations in the study region. The highest increase of T max and T min values were obtained over Kermanshah and Ahwaz at the rates of (+)0.597°C/decade and (+)0.911°C/decade, respectively. On the seasonal scale, the strongest increasing trends were identified in T max and T min data in summer. The highest numbers of stations with positive significant trends occurred in the monthly T max and T min series in August. In contrast, the lowest numbers of stations with significant positive trends were observed between November and March. Overall, the results showed similar increasing trends for the study variables, although T min generally increased at a higher rate than T max in the study period. 相似文献
165.
Hossein Tahghighi 《地震工程与结构动力学》2011,40(14):1591-1608
Unique to the near‐source region of a large earthquake is the occurrence of strong impulsive ground motion and surface faulting referred to as ‘fling‐step’ motion. The objective of this study is to synthesize broad‐band time histories over a wide range of frequencies by characterizing rupture directivity and fling effects from the comprehensive strong motion database of the near‐fault Chi‐Chi event. To aid in the generation of these special types of ground motions, a hybrid modeling technique is introduced based on the stochastic finite‐fault radiation method and an efficient analytical approach to incorporate the observed low‐frequency features in the records close to the ruptured fault. The results show that the overall agreement among the developed hybrid methodology and recorded waveforms and response spectra is quite satisfying. A brief discussion on the design of infrastructures near seismic fault is also included. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
166.
167.
Forough Keshvari Z. Hossein Shomali Mohammad Tatar Ayoub Kaviani 《Journal of Seismology》2011,15(2):329-339
Non-linear teleseismic S-phase tomography across the Zagros collision zone in southwestern Iran is used to determine a high-resolution
image of the upper-mantle structure. The inversion was done using 41 high-quality earthquakes recorded by 19 broad-band and
medium-band stations along a 620 km long profile across the collision zone. Smearing from strong crustal velocity anomalies
into the upper-mantle is suppressed by travel-time corrections calculated based on a 3-D crustal model for the study area.
Our results show that the relatively old and cold Arabian shield has a higher velocity (up to 6% faster, at depths between
70 and 300 km) than the younger lithosphere farther north in Central Iran. These two upper-mantle domains are separated by
a sharp near-vertical transition whose surface expression coinciding with the Main Zagros Thrust. 相似文献
168.
Geochronological and geochemical constraints on the petrogenesis of high-K granite from the Suffi abad area, Sanandaj-Sirjan Zone, NW Iran 总被引:1,自引:0,他引:1
Hossein Azizi Yoshihiro Asahara Behzad Mehrabi Sun Lin Chung 《Chemie der Erde / Geochemistry》2011,71(4):363-376
The Sanandaj-Sirjan Zone (SSZ) trends northwestward in western Iran on the Precambrian to Paleozoic basement and exposes abundant I-type granitoids and calc-alkaline volcanic rocks that were most active during the Late Jurassic to Upper Cretaceous. The petrogenesis of the granitoids and associated volcanic rocks has been widely related to Neotethyan subduction beneath the Iranian plate. We report a geochronological and geochemical study of the Suffi abad granite (SLG) body that crops outs southeast of Sanandaj within the SSZ and is mainly composed of K-feldspar + quartz + plagioclase ± hornblende. The SLG, which shows a high-K calc-alkaline affinity, has LA-ICPMS zircon U–Pb ages ranging between 149 ± 2 and 144 ± 3 Ma and initial 87Sr/86Sr of ∼0.7024–0.7069 and 143Nd/144Nd of ∼0.5125–0.5127. These value correspond to an ?Nd (145 Ma) of +1.5 and +4.9, suggesting that the SLG originated from the juvenile crust or depleted mantle with a young TDM (650–900 Ma) over the subduction zone beneath the SSZ. Zircon saturation temperatures suggest that crystallization of the zircons, or emplacement of the host magmas, occurred at 560–750 °C, consistent with an intergrowth texture of K-feldspar and quartz that implies crystallization around the K-feldspar-quartz eutectic at lower temperatures. Overall, geochemical data suggest that crystallization of the hornblende and plagioclase played a role in magma differentiation. These data allow us to conclude that the high-K SLG did not originate directly from the juvenile mantle source as do most I-type, calc-alkaline granitoids, but more likely was produced from the partial melting of pre-existing I-type granitoids in the upper continental crust under low pressure conditions. 相似文献
169.
Azadeh Agah Faramarz Doulati Ardejani Hossein Ghoreishi 《Arabian Journal of Geosciences》2013,6(6):1933-1944
This paper presents a two-dimensional finite volume model to predict multi-species reactive transport processes in the saturated zone of a simulated semi-confined aquifer. A multipurpose commercial software called PHOENICS was used to solve model equations numerically. Capability of the present model was first confirmed using experimental data and the results obtained by a published one-dimensional finite element reactive transport model by other researchers taking different scenarios into consideration. The model was then expanded to a two-dimensional case to simulate reactive transport of BTX compounds with discontinuous source in the saturated zone of the groundwater flow system. In addition to the physical transport processes, the two-dimensional model also incorporates linear and nonlinear adsorption isotherms, first order and Monod kinetics. The two-dimensional model considers both static and dynamics modes into account. The results show that considering chemical reactions during reactive transport of contaminants could successfully predict the contaminated zone. The results of such studies can be used for monitoring of contaminated areas, designing methods to control pollution transport, and minimize its harmful effects on aquifer systems. 相似文献
170.
Hossein Molhem Mirsattar Meshinchi-Asl Mohammad Ali Jafarizadeh 《Arabian Journal of Geosciences》2013,6(8):2971-2979
Time domain electromagnetic (TDEM) response of a conductive permeable sphere is a main topic for good understanding and in developing past studies for detection and discrimination of buried metallic objects. Stochastic differential equation model is a valuable tool for stimulating real experience. In this paper, according to an Itô integral, we have obtained a weak approximation of stochastic TDEM response of permeable and nonpermeable sphere. We have used the deterministic solution of TDEM response of conductive permeable sphere by changing one of the variables that have been obtained from the boundary conditions of problem to random variable. By adding white noise to random variable and using stochastic integral, we have displayed stochastic time domain response of conductive permeable sphere. The Itô integral includes a factor that shows infirmity and intensity of noise which has been simply considered constant. Accordingly, we have showed the effect of noise for magnetic and nonmagnetic spheres. Numerical results from step and impulse response of TDEM have shown that the amount of this factor is different for the two types of spheres. 相似文献