Aftershock probabilistic seismic hazard analysis for Bushehr province in Iran using ETAS model

Natural Hazards - Aftershock probabilistic seismic hazard analysis (APSHA) has a key role in risk management after a major earthquake. The main goal of the current study is to assess aftershock...     

Identification of geochemical anomalies by using of number–size (N–S) fractal model in Bardaskan area, NE Iran

Geochemical anomaly separation and identification using the number–size (N–S) model at Bardaskan area, NE Iran is studied in this paper. Lithogeochemical data were used in this study which was conducted for the exploration for Au and Cu mineralization and enrichments in Bardaskan area. There are two major mineralization phases concluded epithermal gold and a disseminated systems. N–S log–log plots for Cu, Au, Sb, and As illustrated multifractal natures. Several anomalies at local scale were identified for Au (32 ppb), Cu (28 ppm), As (11 ppm), and Sb (0.8 ppm) and the obtained results suggest existence of local Au and Cu anomalies whose magnitudes generally are above 158 and 354 ppm, respectively. The most important mineralization events are responsible for presence of Au and Cu at grades above 1,778 and 8,912 ppm. The study reveals threshold values for Au and Cu are a consequence of the occurrence of anomalous accumulations of phyllic and silicification alteration zones and metamorphic rocks especially in tuffaceous sandstones and sericite schist types. The obtained results were correlated with fault distribution patterns, revealing a positive direct correlation between mineralization in anomalous areas and the faults present in the mineralized system.     

CFD modeling of the launder of settler of an industrial copper solvent extraction plant: A case study on Sarcheshmeh copper complex,Iran

In this study, a computational fluid dynamics (CFD) modeling accompanied by experimental field measurements has been applied to study the behavior of aqueous–organic dispersion on the performance of the launder of the settler of the copper solvent extraction plant at the Sarcheshmeh copper complex, Iran. Fluid flow field has been calculated by solving the continuity and Navier Stokes equations along with the standard k-ε turbulence model. The simulation results have been compared with the field measurements data to check the accuracy of the CFD work. The effects of picket fence on the launder performance and pressure drop over the picket fences in the launder have been investigated. The model predicts that by setting the picket fences, flow pattern becomes uniform, and turbulent eddies disappear. The results also show that by installing two picket fences without dam in the launder, the phase separation is improved and the performance of the launder is optimized.     

Health risk assessments due to nitrate levels in drinking water in villages of Azadshahr,northeastern Iran

Groundwater is the main water source used for drinking and cooking purposes globally. Nitrate level in most groundwater resources in arid and semi-arid areas has increased in the past several decades as a result of human activities and natural processes. This may exert a great impact on human health. To learn the contamination circumstances of groundwater nitrate in villages of Azadshahr, Iran and assess its probable risk to the health of adults, children and infants, fifty-eight groundwater samples were collected from wells and springs in 2018. Nitrate concentrations had a wide spatial variability in wells and springs of the studied villages, with values going from 1 up to 51 mg/L. Exceedances of the EPA standard value were limited to two village springs (villages Nili and Narab, with nitrate level of 51 and 46 mg/L, respectively). The hazard quotients (HQ) values for 41% of children and infants were above the safety level (i.e., HQ?>?1), suggesting that groundwater nitrate would have significant health effects on these age groups. Therefore, appropriate control measures and sanitation improvement programs should be put in place to protect the health of the residents in the contaminated villages.     

Emotional and cognitive factors influencing flood preparedness in Dire Dawa town,Ethiopia

Traditional approaches to risk communication ignore the emotional, cognitive and social factors that interact to influence the meaning people attribute to hazards and protective actions. The aim of this study was to investigate the emotional and cognitive factors predicting preparedness intention and community’s preparedness for flood hazards. A cross-sectional study was conducted between June and July 2015, in Dire Dawa town, Ethiopia. Using stratified systematic random sampling, a structured questionnaire was administered to individuals aged 18 and over in 660 households. Data were analyzed using structural equation modeling (SEM) (STATA version 13.0). The study participants’ mean age was 34 years, ranging from 18 to 80 (SD?=?12) with equal gender balance. SEM analysis revealed that the total effects of preparedness intention (path coefficient (β)?=?0.202, 95% CI: [0.036, 0.369]), past flood disaster experience (β?=?0.034, 95% CI: [0.008, 0.061]), trust (β?=?0.100, 95% CI: [0.059, 0.142]), anxiety (β?=?0.026, 95% CI: [0.018, 0.034), positive outcome expectancy (β?=???0.139, 95% CI: [??0.253, ??0.026]), negative outcome expectancy (β?=?0.105, 95% CI: [0.062, 0.149]), perceived flood likelihood (β?=?0.049, 95% CI: [0.012, 0.086]) and consequence (β?=???0.040, 95% CI: [??0.077, ??0.003]) on community preparedness for flood hazards were statistically significant. The main implication of these findings is that people affected by hazard events in the past experience more anxiety and are more likely to participate in community preparedness activities than those who were not affected.     

Paleoenvironmental conditions of Early Miocene corals,western Makran,Iran

Miocene coral-bearing limestones, distributed in the western Makran Basin, are attributed to Aquitanian and Burdigalian. This investigation is focused on three Early Miocene coral-bearing limestone sections in western Makran. Remarkably, well-preserved scleractinian corals and other components could be very definitive to reconstruct paleoenvironmental conditions. Lithologically, there are some differences between the studied sections. Furthermore, zooxanthellate corals are diverse and abundant in all sections. Based on different components and richness of zooxanthellate corals, it seems that the studied carbonate corals are precipitated in a subtropical condition, between 19 and 20 °C in all sections. In light of the dominancy of corals, the presence of symbiont-bearing larger benthic foraminifera (LBF), lithological features, bioeroding features, and encrusting organisms, the oligotrophic to slightly mesotrophic conditions are considered for Tejek section and the mesotrophic condition had been prevailed in Kermestan and Irer sections. According to light intensity in water column and coral morphotypes, Tejek section is considered to precipitate under euphotic to slightly mesophotic condition, while Kermestan and Irer sections were deposited under mesophotic to euphotic light conditions. In transparent water, photic zones continue to deeper depths, while in less transparent water, these zones are limited to shallower parts. A defined depth in the photic zone may represent euphotic, mesophotic, or oligophotic zone. Based on the water transparency, a taxon in a defined photic zone can occur in various depths. On the basis of trophic-light intensity-depth chart, the estimated depth ranges are 12–85 m for Tejek section and 5–62 m for Kermestan and Irer sections. Water energy as another important factor in environmental condition is acquired from coral morphotypes. Accordingly, Tejek section is precipitated under moderate-high energy and Kermestan and Irer sections are deposited in low to moderate-high energy. The presence of encrusting coralline algae, corals, and other constituents is indicative of different substrates in the studied areas. Corals favorably develop in normal salinity waters. The existence of colonial corals and occurrence of benthic foraminifera with hyaline wall indicate normal seawater conditions.     

Application of 3D Numerical Model and Intelligent Systems in Discharge Coefficient Estimation of Combined Weir-Gate

Water Resources - Combined weir-gate structure is one of the important structures which are control the water level, measure discharge and avoid sediment deposition behind the weir. In this study,...