Worst scenarios of tsunami effects along the Mediterranean coast of Egypt

Scenarios of tsunami effects represent a very useful technique for the definition and evaluation of tsunami hazard and risk for the Egyptian coast. This paper is an attempt to develop different worst scenarios of tsunamigenesis toward the Egyptian Coast for five segment localities along three different sub-regions (Hellenic Arc, Cyprean Arc and Levantine Coast) in the eastern Mediterranean Sea. These segments are the southwest Hellenic Arc, southeast Hellenic Arc, northeast Hellenic Arc, west of Cyprean Arc and Levantine. For each of them, the scenario takes into account a seismic fault capable of generating an earthquake with magnitude equal to or larger than the highest magnitude registered in that region in historical times. Then the ensuing tsunamis are simulated numerically, highlighting the basic features of the wave propagation and roughly identifying the coastal sectors that are expected to suffer the heaviest tsunami effects. The output data indicated that the first wave of tsunamis from different segments attacked the nearest reference localities (city located nearest each segment) along the Egyptian shore between 28 and 50 min after an earthquake. Tsunamis from these earthquake scenarios produced maximum run-up heights ranging from 1.7 to 9.4 m at the shore. A Beirut Thrust scenario (Levantine segment) included the fact that only a small portion of the fault extended out into the sea, leading to a small effective tsunami source area. In contrast, the southwest Hellenic Arc segment (as in the A.D. 365 earthquake) has high displacement (15 m) and a long extensional fault, forming a highly effective tsunami source area.     

Temporal and spatial distribution of dissolved Cu, Ni and Zn in the coastal waters of Jeddah, eastern Red Sea

Dissolved Cu, Ni, and Zn were measured in the surface coastal waters of Jeddah, eastern Red Sea during October 2004 and April 2005. High values of trace metals, particularly Zn, were recorded in the Southern Corniche area close to a sewage effluent indicating a significant contribution from the wastewater. Concentrations of trace metals decreased northward and southward under the effect of dilution. Another hot spot was also observed in the vicinity of Jeddah Desalination Plant (JDP) during April 2005 indicating a possible contribution from the JDP to trace metal contents in the study area. Trace metals were correlated to salinity, nutrients and particulate organic carbon (POC). The good association between Zn and reactive silicate and Ni and ammonium is attributed to simultaneous biological utilization and regeneration. The behavior of copper suggested adsorption of Cu onto the POC during October 2004 whereas in April 2005 the most important process seems to be desorption of Cu from the particulate materials.     

The seabed characteristics of the bottom floor of Damietta Branch,Egypt, using acoustic signals

The study area lies between 31.32°N, 31.70°E and 31.41°N, 31.78°E along Damietta branch, Nile River. It is about 24-km long. Acoustic classification (Quester Tangent Corporation—QTC) is used as a powerful tool to study seabed characteristics which is confirmed by the sediment analyses. Sediment characteristics of the study are presented by three acoustic classes: sand, mud and organic matter intercalated by clay. The depth varies from about ?12 m at Faraskour Bridge (southern part of the study area) to about ?2.5 m at Faraskour Dam (northern part of the study area). The average current velocity is detected as 4 cm/s and it has a very low effect on the transport of both sediment and waste debris. The sediment in the northern part characterized by organic matter reaches about 70 cm thickness under and around fish cages. This huge amount of organic matter deposit leads to the reduction of the dissolved oxygen and increase pH values. This study shows that the water quality in the northern part of the study area is at risk (drinking water for Damietta city) due to the presence of the huge amount of waste debris intercalated by organic matter. The rises of temperature in summer enhance oxygen consumption and the decomposition of the organic matter. This is rapidly increasing the growth of bacteria and phytoplankton, causing turbidity and algal blooms. Those affect the water quality and raise the water toxicity (drinking water).     

Closest Approach in Universal Variables

In this paper, universal formulations of the closest approach problem are established and solved by two methods. The first method uses the technique of one-dimensional unconstraint minimization and needs the solution of the universal Kepler's equation twice, while for the second method, a constraint minimization technique is developed and needs the solution of two nonlinear simultaneous equations. Flexible iterative schemes of quadratic up to any positive integer order are developed for the solution of the universal Kepler's equation. The two methods of the minimization process are applied for the closest approach of Hyakutake and Hale–Bopp comets, while the first method is applied to obtain the minimum angular separation of ADS 9159, ADS 2959 and ADS 11632 visual binaries as typical examples of elliptic, parabolic and hyperbolic orbits. This revised version was published online in July 2006 with corrections to the Cover Date.     

Determination and prediction of standardized precipitation index (SPI) using TRMM data in arid ecosystems

Drought over a period threatens the water resources, agriculture, and socioeconomic activities. Therefore, it is crucial for decision makers to have a realistic anticipation of drought events to mitigate its impacts. Hence, this research aims at using the standardized precipitation index (SPI) to predict drought through time series analysis techniques. These adopted techniques are autoregressive integrating moving average (ARIMA) and feed-forward backpropagation neural network (FBNN) with different activation functions (sigmoid, bipolar sigmoid, and hyperbolic tangent). After that, the adequacy of these two techniques in predicting the drought conditions has been examined under arid ecosystems. The monthly precipitation data used in calculating the SPI time series (SPI 3, 6, 12, and 24 timescales) have been obtained from the tropical rainfall measuring mission (TRMM). The prediction of SPI was carried out and compared over six lead times from 1 to 6 using the model performance statistics (coefficient of correlation (R), mean absolute error (MAE), and root mean square error (RMSE)). The overall results prove an excellent performance of both predicting models for anticipating the drought conditions concerning model accuracy measures. Despite this, the FBNN models remain somewhat better than ARIMA models with R?≥?0.7865, MAE?≤?1.0637, and RMSE?≤?1.2466. Additionally, the FBNN based on hyperbolic tangent activation function demonstrated the best similarity between actual and predicted for SPI 24 by 98.44%. Eventually, all the activation function of FBNN models has good results respecting the SPI prediction with a small degree of variation among timescales. Therefore, any of these activation functions can be used equally even if the sigmoid and bipolar sigmoid functions are manifesting less adjusted R² and higher errors (MAE and RMSE). In conclusion, the FBNN can be considered a promising technique for predicting the SPI as a drought monitoring index under arid ecosystems.     

Kernel distributed residual function in a revised multiple order autoregressive model and its applications in hydrology

ABSTRACT

This paper describes a new approach to fill missing data in hydrologic series. Based on a multiple-order autoregressive model, our algorithm represents the random term with an empirical distribution function that includes different parameters for the low, medium and high ranges of the modelled hydrologic variable. The algorithm involves a corrective mechanism that preserves the original statistical distribution of the series that are filled, while also eliminating the possibility of obtaining negative values for low flows. The algorithm requires multiple correlated hydrologic time series with sufficient data to permit accurate calculation of their statistical properties. It ensures that both the original statistical dependence among the data series and the statistical distribution functions will be preserved after the missing data had been filled. The model has been tested using 15 streamflow series in the Upper Bow River watershed in Alberta, Canada.     

Unified Symbolic Algorithm of Gauss Method for Near-Parabolic Orbits

In this paper, a unified algorithm of Gauss method for near‐parabolic orbits that is valid for both elliptic and hyperbolic cases is established symbolically and numerically. This revised version was published online in July 2006 with corrections to the Cover Date.     

Simulation of temporal variation for reference evapotranspiration under arid climate

Interpretation of 2500 km of newly processed 2D seismic and regional potential field data has led to the identification of two new Miocene–Oligocene sedimentary basins in the northern part of offshore Egypt. The western part of the basin is deeper and has thick sedimentary cover. The upper part of the Miocene section is tested in its southern part through two wells, where the eastern subbasin is still virgin and is located at the intersection between Temsah basins and southeastern end of the Levantine basin. The main sedimentary unit of the basin is the Miocene–Oligocene sedimentary section, which was proven by the exploration and production activities in Nile Delta to be one of the hydrocarbon-generating facies. This fact is supported by 1D basin analysis using the average parameter values, which shows a hydrocarbon window, extending from lower Miocene to upper Miocene. The basin dimensions are more than 2000 km² area and more than 4000 m of thickness, with variable petroleum system parameters’ potentialities, starting from Tortonian–Serravallian to lower Oligocene section.

     

A reanalysis of the AD 365 tsunami impact along the Egyptian Mediterranean coast

The historical tsunamigenic event of 21 July AD 365 destroyed several coastal locations in the Eastern Mediterranean region. The foremost destructive impacts were recorded in Crete and Egypt. The present study re-examines the effect of location, direction, height and time of travel of the tsunami towards the Egyptian coast. Evidently, this tsunamigenic event is related to an earthquake which is identified with a Hellenic Arc subduction-zone event of great magnitude, M > 8, as manifested by up to 9 m uplift in western Crete. The maximum run-up height distribution in the front of the Nile Delta was about 9.5 m in Alexandria, while those of the neighboring cities were 7.1 m, 4.9 m, and 1.9 m at Rashid, Damietta and El-Arish, respectively. Data obtained from this study is essential to evaluate the tsunami hazards along the Egyptian coast.     

Parametric time‐domain identification of multiple‐input systems using decoupled output signals

Civil engineering structures are often subjected to multidirectional actions such as earthquake ground motion, which lead to complex structural responses. The contributions from the latter multidirectional actions to the response are highly coupled, leading to a MIMO system identification problem. Compared with single‐input, multiple‐output (SIMO) system identification, MIMO problems are more computationally complex and error prone. In this paper, a new system identification strategy is proposed for civil engineering structures with multiple inputs that induce strong coupling in the response. The proposed solution comprises converting the MIMO problem into separate SIMO problems, decoupling the outputs by extracting the contribution from the respective input signals to the outputs. To this end, a QR factorization‐based decoupling method is employed, and its performance is examined. Three factors, which affect the accuracy of the decoupling result, including memory length, input correlation, and system damping, are investigated. Additionally, a system identification method that combines the autoregressive model with exogenous input (ARX) and the Eigensystem Realization Algorithm (ERA) is proposed. The associated extended modal amplitude coherence and modal phase collinearity are used to delineate the structural and noise modes in the fitted ARX model. The efficacy of the ARX‐ERA method is then demonstrated through identification of the modal properties of a highway overcrossing bridge. Copyright © 2013 John Wiley & Sons, Ltd.