Tidal asymmetry in a tidal creek with mixed mainly semidiurnal tide,Bushehr Port,Persian Gulf     

Seyed Taleb Hosseini  Vahid Chegini  Masoud Sadrinasab  Seyed Mostafa Siadatmousavi  Sadegh Yari 《Ocean Science Journal》2016,51(2):195-208

This study investigated the tidal asymmetry imposed by both the interaction of principal tides and the higher harmonics generated by distortions within a tidal creek network with mixed mainly semidiurnal tide in the Bushehr Port, Persian Gulf. Since velocity and water-level imposed by principal triad tides K₁-O₁-M₂ are in quadrature, duration asymmetries during a tidal period in this short, shallow inverse estuary should be manifest as skewed velocities. The principal tides produce periodic asymmetries including a strong ebb-dominance and a weak flood-dominance condition during spring and neap tides respectively. The higher harmonics induced by nonlinearities engender a flood-dominance condition where the convergence effects are higher than frictional effects, and an ebbdominance condition where intertidal storage are extended. Since the triad K₁-O₁-M₂ driven asymmetry is not overcome by higher harmonics close to the mouth, the periodic asymmetry dominates within the creek in which higher harmonics reinforce the weak flood-dominance (strong ebb-dominance) condition in the convergent channel (divergent area). Also, the maximum flood and the maximum ebb from all harmonic constituents occurred close to high water slack time during both spring and neap tides in this short creek. Since occational wetting of intertidal areas happened close to the high water (HW) time during spring tide, the water level flooded slowly close to the HW time of the spring tide.  相似文献   

Source mechanism and parameters of the 19 October 2012 earthquake,northern Egyptian continental margin     

Awad Hassoup  Mostafa Toni  M. M. F. Shokry  A. M. A. Helal  Emad K. Mohamed 《Arabian Journal of Geosciences》2016,9(4):313

The 19 October 2012 earthquake (M _L = 5.1) occurred in the northern continental margin of Egypt within the Nile Cone at latitude 32.35° N and longitude 31.27° E. The quake was felt over a wide area in north Egypt and East Mediterranean countries, but no casualties have been reported. This area had experienced the large earthquake (Ms = 6.7) of 12 September 1955. The fault plane solution of the 19 October 2012 earthquake is here presented based on the digital seismograms recorded by the Egyptian National Seismological Network (ENSN) and other regional seismic stations. The analysis is carried out using the well-known techniques of first motion polarities of P-wave and the amplitude ratios of P-, SH-, and SV-waves with lower hemisphere projection. The fault plane solution based on the first P-wave onset demonstrates a left lateral strike-slip faulting mechanism, while the solution based on both P-wave polarities and amplitude ratios of P-, SH-, and SV-waves reveals a reverse fault with strike-slip component trending NW–SE to NE–SW, in conformity with the N–S compression along the Hellenic Arc convergence zone. Following the Brune’s model, the source dynamic parameters for the 19 October 2012 earthquake are estimated as corner frequency = 1.47 Hz, fault radius = 0.7 km, stress drop = 22.1 MPa, seismic moment = 2.80E + 16 Nm, and moment magnitude M _w = 4.9. These parameters may provide important quantitative information for the seismic hazard assessment studies.  相似文献   

Assessment of failure mechanisms in deep longwall faces based on mining-induced seismicity     

Satar Mahdevari  Kourosh Shahriar  Mostafa Sharifzadeh  Dwayne D. Tannant 《Arabian Journal of Geosciences》2016,9(18):709

Failure mechanisms of the rock mass in the regions of maximum stress concentrations around a longwall face were assessed. In this respect, seismic events that result from changes in the stress field were analyzed to gain more knowledge about rock failure mechanisms in the proximity of the face area. A deep longwall mine developed at depths of about 3–3.5 km in South Africa was selected as a case study. Seismic moment tensor solutions were obtained for 32 seismic events with moment magnitudes in the range of 0.49 and 2.10. Through moment tensor decomposition, the dominant failure mechanisms were investigated by drawing focal mechanism plots. Further analysis was implemented by depicting the corresponding 3D radiation patterns of P-wave particle motions. Although the results cover various failure mechanisms, the dominant mechanisms are shear, implosional, and compressional failures. According to the results, most of the maximum principal stresses in the mine are compressive and oriented nearly vertical, which are in accordance with the gravitational collapses of the mined out areas. The results obtained from this research show that measuring and analyzing mining-induced seismicity can be a reliable measure to characterize the dominant failure mechanisms in a nondestructive manner and to provide a useful assessment of the stability of the longwall face in advance of extraction.  相似文献   

Sea Level Change Analysis and Models Identification Based on Short Tidal Gauge Measurements in Alexandria,Egypt     

Mosbeh R. Kaloop  Mostafa Rabah  Mohamed Elnabwy 《Marine Geodesy》2016,39(1):1-20

Sea level change analysis and models identification are important factors used for coastal engineering applications. Moreover, sea level change modeling is used widely to evaluate and study shoreline and climate changes. This study intends to analyze and model Alexandria, Egypt sea level change by investigating yearly tide gauge data collected in a short duration (2008–2011). The time-frequency method was used to evaluate the meteorological noise frequencies. Two models were used to predict the time series data: Neural Network Autoregressive Moving Average (NNARMA) and Adaptive Neuro-Fuzzy Inference System (ANFIS). The time-frequency analysis and models identification results showed that no extreme events were detected for Alexandria point during the monitoring period. Therefore, the NNARMA and ANFIS models can be used to identify the sea level change. The estimates of the models were compared with the three different statistics, determination coefficient, root mean square errors, and auto-correlation function. Comparison of these results revealed that the NNARMA model performs better than the ANFIS model for the study area.  相似文献   

Correction to: Current and turbulence measurements at the FINO1 offshore wind energy site: analysis using 5-beam ADCPs     

Mostafa Bakhoday-Paskyabi  Ilker Fer  Joachim Reuder 《Ocean Dynamics》2018,68(1):157-157

  相似文献   

Pattern recognition of seismogenic nodes using Kohonen selforganizing map: example in west and south west of Alborz region          下载免费PDF全文

Mostafa Allamehzadeh  Soma Durudi  Leila Mahshadnia 《地震科学（英文版）》2017,30(3):145-155

Pattern recognition of seismic and morphostructural nodes plays an important role in seismic hazard assessment. This is a known fact in seismology that tectonic nodes are prone areas to large earthquake and have this potential. They are identified by morphostructural analysis. In this study, the Alborz region has considered as studied case and locations of future events are forecast based on Kohonen Self-Organized Neural Network. It has been shown how it can predict the location of earthquake, and identifies seismogenic nodes which are prone to earthquake of M5.5+ at the West of Alborz in Iran by using International Institute Earthquake Engineering and Seismology earthquake catalogs data. First, the main faults and tectonic lineaments have been identified based on MZ (land zoning method) method. After that, by using pattern recognition, we generalized past recorded events to future in order to show the region of probable future earthquakes. In other word, hazardous nodes have determined among all nodes by new catalog generated Self-organizing feature maps (SOFM). Our input data are extracted from catalog, consists longitude and latitude of past event between 1980-2015 with magnitude larger or equal to 4.5. It has concluded node D1 is candidate for big earthquakes in comparison with other nodes and other nodes are in lower levels of this potential.  相似文献   

Numerical modelling-based comparison of longitudinal dispersion coefficient formulas for solute transport in rivers     

Mostafa Ramezani  Farhad Hooshyaripor  Zhiqiang Deng  Amin Sarang 《水文科学杂志》2019,64(7):808-819

River water quality models usually apply the Fischer equation to determine the longitudinal dispersion coefficient (D_x) in solving the advection–dispersion equation (ADE). Recently, more accurate formulas have been introduced to determine D_x in rivers, which could strongly affect the accuracy of the ADE results. A numerical modelling-based approach is presented to evaluate the performance of various D_x formulas using the ADE. This approach consists of a finite difference approximation of the ADE, a MATLAB code and a MS Excel interface; it was tested against the analytical ADE solution and demonstrated using eight well-known D_x formulas and tracer study data for the Chattahoochee River (USA), the Severn (UK) and the Athabasca (Canada). The results show that D_x has an important effect on tracer concentrations simulated with the ADE. Comparison between the simulated and measured concentrations confirms the appropriate performance of Zeng and Huai’s formula for D_x estimation. Use of the newly proposed equations for D_x estimation could enhance the accuracy of solving the ADE.  相似文献   

Application of fuzzy Delphi AHP method for the estimation and classification of Ghomrud tunnel from groundwater flow hazard     

Ali Aalianvari  Homayoon Katibeh  Mostafa Sharifzadeh 《Arabian Journal of Geosciences》2012,5(2):275-284

Water inflow and water pressure controls are needed in the design, construction, and exploitation of tunnels. The objective of this paper is to present a new system which can be appropriate for rating tunnel sites to evaluate the potential of groundwater inflow according to the preliminary site investigation data. In this paper, an evaluation model based on combining the analytic hierarchy process and the fuzzy Delphi method has been presented for assessing tunnel site rating from the groundwater hazard point of view. This research treats the tunnel site classification as a group decision problem and applies the fuzzy logic theory as the criterion to calculate the weighting factors. Afterward, the proposed method was successfully applied to determine the amount of groundwater inflow into tunnels. Results of several case studies in various geological conditions roughly show that it can be used to determine the groundwater inflow into tunnels. The introduced method has been examined successfully in Ghomroud tunnel. Results from the proposed method, analytical equations, and observed groundwater inflow into Ghomrud tunnel have been compared. Results show that, because most of parameters regulating groundwater inflow into tunnels have been considered in the method, results from the method are very close to the observed groundwater inflow. Applying this method, according to preliminary investigations conducted by the designers, provides a more suitable design of the drainage system, drilling method, and tunnel support.  相似文献   

Structural and biological control of the Cenozoic epithermal uranium concentrations from the Sierra Pe?a Blanca, Mexico     

Samuel Angiboust  Mostafa Fayek  Ian M. Power  Alfredo Camacho  Georges Calas  Gordon Southam 《Mineralium Deposita》2012,47(8):859-874

Epithermal uranium deposits of the Sierra Pe?a Blanca are classic examples of volcanic-hosted deposits and have been used as natural analogs for radionuclide migration in volcanic settings. We present a new genetic model that incorporates both geochemical and tectonic features of these deposits, including one of the few documented cases of a geochemical signature of biogenic reducing conditions favoring uranium mineralization in an epithermal deposit. Four tectono-magmatic faulting events affected the volcanic pile. Uranium occurrences are associated with breccia zones at the intersection of fault systems. Periodic reactivation of these structures associated with Basin and Range and Rio Grande tectonic events resulted in the mobilization of U and other elements by meteoric fluids heated by geothermal activity. Focused along breccia zones, these fluids precipitated under reducing conditions several generations of pyrite and uraninite together with kaolinite. Oxygen isotopic data indicate a low formation temperature of uraninite, 45–55°C for the uraninite from the ore body and ～20°C for late uraninite hosted by the underlying conglomerate. There is geochemical evidence for biological activity being at the origin of these reducing conditions, as shown by low δ³⁴S values (～?24.5‰) in pyrites and the presence of low δ¹³C (～?24‰) values in microbial patches intimately associated with uraninite. These data show that tectonic activity coupled with microbial activity can play a major role in the formation of epithermal uranium deposits in unusual near-surface environments.  相似文献   

Numerical simulation of waves in the Caspian Sea: calibration and verification of the observation-based source terms     

Alipour  Atefeh  Siadatmousavi  Seyed Mostafa  Jose  Felix 《Ocean Dynamics》2021,71(6-7):699-714

Ocean Dynamics - Third-generation models employ a host of parameterization schemes to consider the input wind forcing and the wave energy dissipation under different physical settings and...  相似文献