The status of geography in Saudi universities with special reference to King Saud University

Although there are several departments and subdepartments of geography in Saudi universities and other institutions, these departments have so far failed to produce professionals who are capable of filling the posts offered by the employers in both the public and private sectors. This paper suggests that since the demand for geography graduates with general training is rather low at presents, it is time for geography departments to turn to professionalism in the field so that geography graduates can compete favourably for the available posts. This calls for a new look into the geography curriculum, particularly at university level with a view of improving the skills and aptitude of geographers to assume a more positive role in the process of development. The paper also calls for the regional specialisation of geography departments in Saudi Arabia as a step forward towards solving the existing job problem for geography graduates, as well aas underlining the involvement and commitment of geographers to issues of development at the local, regional and national scales.     

A Preliminary Survey of the Nitrogen and Carbon Isotope Characteristics of Fish from the Lagoons of Egypt’s Nile Delta

The present study reports nitrogen and carbon stable isotope data (δ¹⁵N and δ¹³C) from four large (63–400 km²), shallow (∼1 m) coastal lagoons on Egypt’s Nile Delta. While the lagoons all receive sewage and agricultural drainage, the magnitude of loading varies. In this preliminary survey, we document wide variability in the δ¹⁵N and δ¹³C isotope values of major fish groups among these lagoons. There were no consistent or significant differences among the major groups of fish, including carp, catfish, mullet, and tilapia. There was a strong positive correlation (R ² = 0.84) between the average δ¹⁵N values of fish muscle and estimated water residence time among the lagoons. This preliminary evidence suggests that nitrogen cycle transformations may be more important than primary N source differences in determining N isotopic ratios of organisms in the lagoons. The δ¹³C results point to the probable importance of autochthonous particulate organic matter rather than terrestrial detritus or marine plankton in the diets of resident fish populations in the lagoons.     

The 1992 Cairo earthquake: A case study of a small destructive event

On 12 October 1992, an earthquake, magnitude mb = 5.9 and M s = 5.2, hit the City of Cairo, Egypt. It was this century's largest earthquake in northern Egypt with related destruction in the City of Cairo, the Nile Valley and the Nile Delta areas. Our source parameter determinations show that the 1992 earthquake had a normal faulting mechanism, seismic moment M o = 5.2 × 1017 Nm, centroid depth of 23 km and a source time function duration of 3 seconds. The mechanism is compared with those corresponding to two other events that occurred in the northern Red Sea. The similarity between the mechanisms as well as the spatial distribution of the geological faults around Cairo suggest seismic activity along the extension of the stress field of the Red Sea rift system to the area around the City of Cairo. This situation affects the level of seismic hazard in the Cairo area. The 1992 earthquake belongs to an unusual class of relatively small, M w > 6.0, yet destructive earthquakes. The damage caused by these events is usually attributed to their shallow focal depth, 5 km, and to amplification of seismic waves in the local soil beneath the damaged structures. However, the Cairo earthquake deviates from other events of this class since the focal depth was determined to be 23 km. We calculated synthetic accelerograms for the 1992 earthquake with the loose sediments observed in the Nile Valley, and show that this enhanced the amplitude of the acceleration by a factor of two. However, the determined accelerations, about 0.5 m s-2, cannot alone explain the relatively large amount of damaged structures. Hence, a major cause to the destruction is likely the poor state of construction of the Cairo buildings.     

Seismicity and Seismic Hazard in Alexandria (Egypt) and its Surroundings

— Alexandria City has suffered great damage due to earthquakes from near and distant sources, both in historical and recent times. Sometimes the source of such damages is not well known. Seismogenic zones such as the Red Sea, Gulf of Aqaba-Dead Sea Hellenic Arc, Suez-Cairo-Alexandria, Eastern-Mediterranean-Cairo-Faiyoum and the Egyptian costal area are located in the vicinity of this city. The Egyptian coastal zone has the lowest seismicity, and therefore, its tectonic setting is not well known. The 1998 Egyptian costal zone earthquake is a moderate complex source. It is composed of two subevents separated by 4 sec. The first subevent initiated at a depth of 28 km and caused a rupture of strike (347°), dip (29°) and slip (125°). The second subevent occurred at a shallower depth (24 km) and has a relatively different focal parameter (strike 334°, dip 60° and slip 60°). The available focal mechanisms strongly support the manifestation of a complex stress regime from the Hellenic Arc into the Alexandria offshore area. In the present study a numerical modeling technique is applied to estimate quantitative seismic hazard in Alexandria. In terms of seismic hazard, both local and remote earthquakes have a tremendous affect on this city. A local earthquake with magnitude M_s = 6.7 at the offshore area gives peak ground acceleration up to 300 cm/sec². The total duration of shaking expected from such an earthquake is about three seconds. The Fourier amplitude spectra of the ground acceleration reveals that the maximum energy is carried by the low frequency (1–3 Hz), part of the seismic waves. The largest response spectra at Alexandria city is within this frequency band. The computed ground accelerations due to strong earthquakes in the Hellenic Arc, Red Sea and Gulf of Aqaba are very small (less than 10 cm/sec²) although with long duration (up to 3 minutes).     

Gram Stain Index (GSI) of Bacterial and Archaeal Cells in the Natural Microbial Communities of Slightly and Extremely Saline Environments

The use of GSI (Gram Stain Index) was studied for natural microbial cells in slightly and extremely saline environments. The GSI spectra of archaeal cells in an extremely saline environment showed unique profiles, different from those of Bacteria. These profiles can be applied for structural analysis of the microbial communities in aquatic environments.     

Motion of artificial satellites in the set of Eulerian redundant parameters (III)

In this paper, the classical and generalized Sundman time transformations are used to establish new generating set of differential equations of motion in terms of the Eulerian redundant parameters. The implementation of this set on digital computers for the commonly used independent variables is developed once and for all. Motion prediction algorithms based on these equations are developed in a recursive manner for the motions in the Earth's gravitational field with axial symmetry whatever the number of the zonal harmonic terms may be. Applications for the two types of short and long term predictions are considered for the perturbed motion in the Earth's gravitational field with axial symmetry with zonal harmonic terms up to J ₃₆ . Numerical results proved the very high efficiency and flexibility of the developed equations.     

Distribution of the energy release, b-values and seismic hazard in Egypt

A review of the seismicity and seismic history of Egypt indicates areas of high activity concentrated along Oligocene-Miocene faults. This supports the idea of recent activation of the Oligocene-Miocene stress cycle. There are similarities in the spatial distribution of recent and historical epicenters. Destructive earthquakes in Egypt are mostly concentrated in the highly populated areas of the Nile Valley and Nile Delta. Some big earthquakes located near the plate boundary as far away as Turkey and Crete were strongly felt in Egypt. The distribution of the energy release shows a possible tectonic connection between active zones in Egypt and the complicated tectonic zones in Turkey and Crete through geologically verified fault systems. The distribution of intensity shows a strong directivity along the Nile Valley. This is due to the presence of a thick layer of loose sediments on top of the hard rock in the Nile Valley graben. The distribution of b-values indicates two different zones, comparable with stable and unstable shelf areas. Stress loads in the northern Red Sea and northern Egypt are similar. Geologically, northern Egypt is a part of the Unstable Shelf area. The probability to have an earthquake with intensity V or larger within 94 years is more than 80% in the Nile Valley and Nile Delta areas, Egypt-Mediterranean coastal area, Aswan High Dam area, Gulf of Aqaba-Levant Fault zone and in the oil fields of the Gulf of Suez. The maximum expected intensity in these areas and within the same period is V–VI for a 80% probability and VII–VIII+ for a 10% probability. Intensity VIII–IX has been reported for several earthquakes in both historical and recent time.