Fault parameters and macroseismic observations of the May 10, 1997 Ardekul-Ghaen earthquake     

H. Amini  M. Zare  A. Ansari 《Journal of Seismology》2018,22(1):5-19

The Ardekul (Zirkuh) earthquake (May 10, 1997) is the largest recent earthquake that occurred in the Ardekul-Ghaen region of Eastern Iran. The greatest destruction was concentrated around Ardekul, Haji-Abad, Esfargh, Pishbar, Bashiran, Abiz-Qadim, and Fakhr-Abad (completely destroyed). The total surface fault rupture was about 125 km with the longest un-interrupted segment in the south of the region. The maximum horizontal and vertical displacements were reported in Korizan and Bohn-Abad with about 210 and 70 cm, respectively; moreover, other building damages and environmental effects were also reported for this earthquake. In this study, the intensity value XI on the European Macroseismic Scale (EMS) and Environmental Seismic Intensity (ESI) scale was selected for this earthquake according to the maximum effects on macroseismic data points affected by this earthquake. Then, according to its macroseismic data points of this earthquake and Boxer code, some macroseismic parameters including magnitude, location, source dimension, and orientation of this earthquake were also estimated at 7.3, 33.52° N–59.99° E, ~ 75 km long and ~ 21 km wide, and ~ 152°, respectively. As the estimated macroseismic parameters are consistent with the instrumental ones (Global Centroid Moment Tensor (GCMT) location and magnitude equal 33.58° N–60.02° E, and 7.2, respectively), this method and dataset are suggested not only for other instrumental earthquakes, but also for historical events.  相似文献   

Degradation of trace aqueous 4-chloro-2-nitrophenol occurring in pharmaceutical industrial wastewater by ozone   总被引：1，自引：1，他引：0  

P. Gharbani  M. Khosravi Ph.D  S. M. Tabatabaii Ph.D  K. Zare Ph.D  S. Dastmalchi Ph.D  A. Mehrizad 《International Journal of Environmental Science and Technology》2010,7(2):377-384

Degradation of 4-chloro-2-nitro phenol by ozonation in aqueous solution was studied in a semi batch reactor under constant ozone dosage and variable pH conditions. The effectiveness of the process was estimated based on the degree of conversion of 4-chloro-2-nitro phenol. It was observed that ozonation is more effective at alkaline reaction of medium than other conditions. The degree of conversion achieved (at the first 5 minutes of the process)at pH 9 was 99.64% compared to 99.03% and 77.35% at pH 7 and 3, respectively. Another parameter used to quantify the 4-chloro-2-nitrophenol during ozonation was the pseudo first order rate constant k [min^?1]. Results showed that the rate constant of the process was approximately much higher at the alkaline pH compared to acidic ones. A considerable improvement in chemical oxygen demand removal was observed at pH above 7. At pH 9, the reduction in chemical oxygen demand at the end of the process reached 56.9 %. The degree of organically bounded nitrogen conversion to nitrate was higher at pH 3. Of the total organic carbon reduction, 15.89 % was observed at pH 9. The 4-chloro-2-nitro phenol degradation intermediate products were analyzed by mass- spectrometry. The main intermediate product was chlorophenol.  相似文献   

Assessment of seasonal variations of chemical characteristics in surface water using multivariate statistical methods   总被引：5，自引：1，他引：4  

A. Zare Garizi  V. Sheikh Ph.D.  A. Sadoddin Ph.D. 《International Journal of Environmental Science and Technology》2011,8(3):581-592

Water pollution has become a growing threat to human society and natural ecosystems in the recent decades. Assessment of seasonal changes in water quality is important for evaluating temporal variations of river pollution. In this study, seasonal variations of chemical characteristics of surface water for the Chehelchay watershed in northeast of Iran was investigated. Various multivariate statistical techniques, including multivariate analysis of variance, discriminant analysis, principal component analysis and factor analysis were applied to analyze river water quality data set containing 12 parameters recorded during 13 years within 1995–2008. The results showed that river water quality has significant seasonal changes. Discriminant analysis identified most important parameters contributing to seasonal variations of river water quality. The analysis rendered a dramatic data reduction using only five parameters: electrical conductivity, chloride, bicarbonate, sulfate and hardness, which correctly assigned 70.2 % of the observations to their respective seasonal groups. Principal component analysis / factor analysis assisted to recognize the factors or origins responsible for seasonal water quality variations. It was determined that in each season more than 80 % of the total variance is explained by three latent factors standing for salinity, weathering-related processes and alkalinity, respectively. Generally, the analysis of water quality data revealed that the Chehelchay River water chemistry is strongly affected by rock water interaction, hydrologic processes and anthropogenic activities. This study demonstrates the usefulness of multivariate statistical approaches for analysis and interpretation of water quality data, identification of pollution sources and understanding of temporal variations in water quality for effective river water quality management.  相似文献   

Organic geochemistry and source rock potential assessment of Late Paleocene Patala Formation in Margalla Hill Range,North Pakistan     

Shams M.Kamran  WANG Pujun  Nasar Khan  Muhammad Hassan 《世界地质(英文版)》2021,24(4):213-225

Black shales of the Paleocene Patala Formation are proven source rocks for conventional hydrocarbons in southern Potwar Basin of Pakistan and are assumed to be effective source rocks towards north in the Margalla Hill Range of Pakistan. In this regard, the current study focuses on source rock geochemistry of the Paleocene Patala Formation to assess its source rock potential, organic matter types and thermal maturity levels in the Mar-galla Hill Range of North Pakistan. Source rock generative potential, kerogen types and thermal maturation of the analysed rock samples were unraveled by using Rock-Eval pyrolysis Tmax, TOC (total organic carbon) and vitrinite reflectance ( R0 ) analyses. TOC analysis coupled with S2 yield revealed poor to fair source rock quality encountered within the formation. The pyrolysis Tmax vs Hydrogen Index ( HI) , showed mostly Type Ⅲ kerogen dominated by thermally immature to mature organic matter. The HI and genetic potential is low and revealed poor hydrocarbon generation potential of the formation. The S1 vs TOC plots confirm the indigenous nature of the hydrocarbons hosted by Patala Formation. The vitrinite reflectance outcomes indicated immature to mature source rock beds lying in dry gas zone. The HI and OI signatures and abundance of Type Ⅲ kerogen are indica-ting dominance of terrestrial organic matter within the formation. Overall, the investigated Patala Formation ex-posed at the studied section of Margalla Hill Range, Pakistan acts as a poor source rock unit for liquid hydrocar-bon generation but holds prospects for dry gas generation in the study area.  相似文献   

Estimating magnitudes of prehistoric earthquakes and seismic capability of fault from landslide data in Noor valley (central Alborz,Iran)     

Zeynab Asadi  Mehdi Zare 《Natural Hazards》2014,74(2):445-461

Detecting the paleoseismological specifications as well as seismic capability of faults has specific importance in estimating the earthquake hazard in any region. The geomorphic indices are used as indirect procedures in the mountainous area. They are appropriate and applicable methods in recognizing the specifications of active tectonics and evaluating fault seismicity in the mountainous areas. In this regard, giant landslides can be pointed out as proper indices. These landslides are usually related to tectonics and triggered by earthquakes in many cases. In this research, giant landslides existed in Noor valley (central Alborz) have been considered as geomorphological indices for recognizing the seismicity of the region and the seismic capability of its faults. There are four giant landslides in this region (Baladeh, Razan, Vakamar, and Iva) used for the mentioned purpose. No historical earthquake has been reported around Noor valley. However, the existence of giant and old landslides, related to earthquake, indicates the occurrence of numerous prehistoric earthquakes. In this research, three different age classes have been determined (Late Holocene, Early Holocene, and Late Pleistocene) for landslides. By the way, the possibility of identifying multiple earthquakes is provided in this area. The magnitudes of earthquakes are estimated as 7.7 ± 0.49 to 7.9 ± 0.49 based on their relations with maximum volume of displaced material. Regarding the distribution of landslides and other evidences, the eastern segment of Baladeh fault has probably been the main cause of the earthquakes.  相似文献   

Near-source strong motion database catalog for Iran     

Zoya Farajpour  Mehdi Zare  Shahram Pezeshk  Anooshiravan Ansari  Esmael Farzanegan 《Arabian Journal of Geosciences》2018,11(4):80

This paper discusses a newly developed high-quality integrated dataset of shallow earthquake ground motions that occurred in Iran, from 1976 to 2013. A total of 860 three-component strong motion records are processed from 183 earthquake events, moment magnitudes 5.0?≤?M _w ?≤?7.4, and rupture distances of R _RUP  ≤ 120 km. Strong motion data from Iran having special tectonic features and shallow earthquakes with depths less than 35 km are included. This paper presents a thorough procedure used to collect and to generate a database following the Next-Generation Attenuation-West research projects. This database can be used in the development and ranking of ground motion models and for seismological and engineering hazard and risk analyses. Unprocessed strong motion records are obtained from the Iranian Strong Motion Network (ISMN). The time series collected were thoroughly examined through several rounds of quality reviews. The newly generated database includes the peak ground acceleration, peak ground velocity, and pseudo-spectral acceleration for the 5% damped with periods ranging from 0.01 to 10 s. The database also includes ground motion information and source characterization and parameters. This study is the near-source compiled ground motion database that can be used for Iran, and it is consistent with standard worldwide databases.  相似文献   

A regularization of the three-body problem     

S. J. Aarseth  K. Zare 《Celestial Mechanics and Dynamical Astronomy》1974,10(2):185-205

Letr ₁,r ₂,r ₃ be arbitrary coordinates of the non-zero interacting mass-pointsm ₁,m ₂,m ₃ and define the distancesR ₁=|r ₁?r ₃|,R ₂=|r ₂?r ₃|,R=|r ₁?r ₂|. An eight-dimensional regularization of the general three-body problem is given which is based on Kustaanheimo-Stiefel regularization of a single binary and possesses the properties:

1. The equations of motion are regular for the two-body collisionsR ₁→0 orR ₂→0.
2. Provided thatR?R ₁ orR?R ₂, the equations of motion are numerically well behaved for close triple encounters.

Although the requirementR? min (R ₁,R ₂) may involve occasional transformations to physical variables in order to re-label the particles, all integrations are performed in regularized variables. Numerical comparisons with the standard Kustaanheimo-Stiefel regularization show that the new method gives improved accuracy per integration step at no extra computing time for a variety of examples. In addition, time reversal tests indicate that critical triple encounters may now be studied with confidence. The Hamiltonian formulation has been generalized to include the case of perturbed three-body motions and it is anticipated that this procedure will lead to further improvements ofN-body calculations.  相似文献   

Bifurcation points in the planar problem of three bodies     

K. Zare 《Celestial Mechanics and Dynamical Astronomy》1977,16(1):35-38

An essential parameter in the planar problem of three bodies is the product of the square of the angular momentum and of the total energy (c ² H). The role of this parameter, which may be called abifurcation parameter, in establishing regions of possible motions has been shown by Marchal and Saari (1975) and Zare (1976a). There exist critical values of this parameter below which exchange between bodies cannot occur. These critical values may be calledbifurcation points.This paper gives an analytical criterion to obtain these bifurcation points for any given masses of the participating bodies.  相似文献   

Assessing performances of pattern informatics method: a retrospective analysis for Iran and Italy     

M. Y. Radan  H. Hamzehloo  A. Peresan  M. Zare  H. Zafarani 《Natural Hazards》2013,68(2):855-881

Pattern informatics (PI) algorithm, which was introduced at the beginning of past decade, uses instrumental earthquake catalogs to investigate the time-dependent rate of seismicity in the study area and, based on the information from past events, calculates the probabilities for the occurrence of future large earthquakes. The main measure in this method is the number of events above a specified magnitude threshold M _c that is counted over a gridded area. PI has been applied in several regions of the world and different variants of the method have been developed over the past decade. Hence, the problem of formally evaluating and comparing the performances of the different PI variants needs to be addressed from an operational perspective, in order to identify the preferred application scheme and as well as to improve the performances of the method. In this study, PI is applied for the first time to the retrospective analysis of the earthquake catalogs of Iran and Italy, so as to check whether this method could forecast the past large events in these two regions with different level of data completeness and complex seismotectonic setting. The original PI algorithm and one of its modified variants, as well as the relative intensity (RI) model, are used to check the stability and statistical significance of the obtained results. In order to assess and compare the obtained results, the performances of the different PI variants are analyzed considering different evaluation strategies, which turn out to provide significantly different scores even for the same algorithm variant. We show that a critical point in the assessment of the obtained results is related with the definition and quantification of the space uncertainty of the issued forecasts, that is, with the extent of the territory where large earthquakes are to be expected. Accordingly, we emphasize the need for an appropriate definition of the evaluation strategies, clearly and unambiguously indicating the area where a large earthquake has to be expected. The study shows that, with respect to application in Iran and Italy, the performances of PI algorithm (both original and modified variants) are highly dependent on the selected evaluation strategy and do not provide better information than the simple RI model, which does not account for temporal properties of seismicity evolution. The overall performances can be improved by introducing specific thresholds that discard the less active cells; however, being based on some posterior optimization, a rigorous prospective testing is required to assess the forecasting capability of the method. In this paper, we aim to set up the rules for such testing, including advance definition of the evaluation strategy.  相似文献   

Stability Analysis of the 19A Ore Pass at Brunswick Mine Using a Two-Stage Numerical Modeling Approach   总被引：1，自引：0，他引：1  

Kamran Esmaieli  John Hadjigeorgiou  Martin Grenon 《Rock Mechanics and Rock Engineering》2013,46(6):1323-1338

The longevity of ore pass systems is an important consideration in underground mines. This is controlled to a degree by the structural stability of an ore pass which can be compromised by changes in the stress regime and the degree of fracturing of the rock mass. A failure mechanism specific to ore pass systems is damage on the ore pass wall by impact load or wear by material flow. Structural, stress and material flow-induced failure mechanisms interact with severe repercussions, although in most cases one mechanism is more dominant. This paper aims to provide a better understanding of the interaction of ore pass failure mechanisms in an operating mine. This can provide an aid in the design of ore pass systems. A two-stage numerical approach was used for the back analysis of an ore pass at Brunswick mine in Canada. The first stage in the analysis relied on a 3D boundary element analysis to define the stress regime in the vicinity of the ore pass. The second stage used a synthetic rock mass (SRM) model, constructed from a discrete fracture network, generated from quantitative rock mass field data. The fracture network geometry was introduced into a bonded particle model, in a particle flow code (PFC). Subsequently, the ore pass was excavated within the SRM model. A stability analysis quantified the extent of rock mass failure around the ore pass due to the interaction of pre-existing fractures and the failure of the intact rock bridges between these fractures. The resulting asymmetric failure patterns along the length of the ore pass were controlled to a large degree by the in situ fractures. The influence of particle flow impact was integrated into the model by projecting a discrete rock fragment against the ore pass walls represented by the SRM model. The numerical results illustrated that material impact on ore pass walls resulted in localised damage and accelerated the stress-induced failure.  相似文献