Radon distributions in the Hail Region of Northern Saudi Arabia

Indoor radon measurements were carried out in a total of 420 dwellings and 17 schools in Hail region of Saudi Arabia, using NTDs based radon dosimeters. The duration of the measurements was one year, from April 2008 to April 2009. The indoor radon concentrations varied from 4 to 513 Bq/m³ with an overall average of 45 Bq/m³ for all surveyed dwellings. These passive measurements were confirmed by the active measurements. The anomalous concentrations above 200 Bq/m³ were observed in 13 dwellings, representing 3.1 % of the total surveyed dwellings. In Inbowan village alone, it was found that 7.6 % of the dwellings have indoor radon concentration above 200 Bq/m³. The highest average indoor radon concentration of 64 Bq/m³ was found in Inbowan village while the lowest average of 24 Bq/m³ was found in Majasah village. The city of Hail showed an average indoor radon concentration of 49 Bq/m³. The average indoor radon concentration in one area located at the edge of the Aja Mountain in Hail city was 111 Bq/m³. The elevated indoor radon concentrations in many dwellings in the Hail region, prompted us to measure outdoor ground radon in such locations using gas monitor. It was found that radon concentrations at a depth of 0.5 m varied significantly from place to place ranging from 1.2 to 177 kBq/m³. The outdoor radon concentrations are generally correlated with the indoor radon measurements. Radon exhalations from construction materials and soil samples from the Hail region were also measured. It was found that radon exhalations from soil samples are higher than that of construction materials by a factor of at least 3 and reaching up to 11. These results indicate that soil is the main source of indoor radon. Geological interpretations of the results are also given.     

The impact of rainfall distribution patterns on hydrological and hydraulic response in arid regions: case study Medina,Saudi Arabia

Rainfall distribution patterns (RDPs) are crucial for hydrologic design. Hydrologic modeling is based on Soil Conservation Services (SCS) type RDPs (SCS type I, IA, II, and III). SCS type II method is widely used by hydrologists in arid regions. These RDPs were designed for the USA and similar temperate regions. There is no scientific justification for using SCS type II method in arid regions. The consequences of using SCS type II have impacts on the hydrologic and hydraulic modeling studies. The current paper investigates the validity of the SCS type II and in arid regions. New temporal RDPs were applied and compared with SCS type II RDPs. The produced peak discharges, volumes, maximum inundation depths, top widths, and velocities from both approaches were analyzed. An application is made on the protection channel in Taibah and Islamic Universities campuses in Medina, Saudi Arabia. A methodology was followed which included frequency analysis, catchment modeling, hydrological modeling, and hydraulic modeling. Results indicated that there are considerable consequences on infrastructural design, and hydrologic and hydraulic parameters if inappropriate RDPs are used. The investigation confirmed that the SCS type RDPs do not reflect the actual flood features in arid regions.     

The extent of desertification on Saudi Arabia

Desertification is the process that turns productive deserts into non-productive deserts as a result of poor land-management. Desertification reduces the ability of land to support life, affecting wild species, domestic animals, agricultural crops and humans. The reduction in plant cover that accompanies desertification leads to accelerated soil erosion by wind and water. South Africa is losing approximately 300–400 million tons of topsoil every year. As vegetation cover and soil layer are reduced, rain fall impact and run-off increases. This paper discusses the extent of desertification, its potential threat to sustained irrigated agriculture and possible measures adopted to control ongoing desertification processes to minimize the loss of agricultural productivity in an arid country such as the Kingdom of Saudi Arabia.     

Swelling Behaviour of Expansive Shales from the Middle Region of Saudi Arabia

Severe and widespread damage in residential buildings, sidewalks and pavements in various parts of the middle region of Saudi Arabia is caused by the development of heave and swelling pressure in the expansive shales in the region. This paper presents the problems and the geotechnical and physicochemical properties of the tested shales. The swelling potential was determined using various methods. Swell tests were conducted under different loading conditions and following different procedures to quantify the amount of vertical swell and swelling pressure. The conventional one-dimensional oedometer swell tests were performed using three different procedures, namely, free swell, constant volume swell and swell overburden. In addition, swell tests were performed in the stress path triaxial apparatus. Tests under different vertical stresses and confinements were conducted. Vertical swell and swelling pressure obtained from the various methods were compared. The reliability of the different methods for estimation of swelling potential is discussed.     

Segregation and seclusion: the case of compounds for western expatriates in Saudi Arabia

In discussions on the “fragmented city” and the boom of private and guarded neighbourhoods, several authors have stressed the importance of a growing differentiation of lifestyles and “cultural” orientations for this trend. The compounds for western foreigners in Saudi Arabia are explicitly based on the idea of a spatial seclusion of social groups with different “cultural” backgrounds. This study presents an overview of the development of these western enclaves. Narrative interviews with former expatriates provide insights into their daily life, their social relations within the compound, and to the Saudi Arabia behind the gates.     

Seismicity associated with active, new-born, and re-awakening basaltic volcanoes: case review and the possible scenarios for the Harraat volcanic provinces, Saudi Arabia

During April–June 2009, a swarm of more than 30,000 earthquakes struck the Harrat Lunayyir, situated in the north-western end of the Saudi Arabian Harraat, east of the Red Sea. This sharp increase in the seismic activity in the region of ancient basaltic volcanic centers indicated a likelihood of a future eruption. To check the situation, a short review of the best-documented seismic activity associated with active, new-born, and re-awakening basaltic volcanoes is presented in this article. Basing on the review, some regularity in the development of seismic activity associated with basaltic eruptions was formulated. Three stages in the development of seismic activity were identified: preliminary, preceding, and continuous. The duration of preceding stage varies from a few hours for active and re-awakened volcanoes to some weeks for new-born volcanoes and may serve as a criterion for discriminations of different types of basaltic eruptions. The duration of the seismic activity during the 2009 episode at Harrat Lunayyir was longer than any activity preceding the basaltic eruptions of different types. Therefore, the most probable scenario is the arrest of sub-surface intrusion without any eruption in the region of Harrat Lunayyir. The next probable scenario would be the dike injections along the rift zones. The re-awakening of the old Harrat Lunayyir volcano or the birth of a new volcano at Harrat Lunayyir is less probable.     

Public perception of the risk of disasters in a developing economy: the case of Saudi Arabia

Saudi Arabia has in recent years experienced frequent disasters, including flooding, epidemics, and dust storms, while many parts of the country are subject to regular earthquake and volcanic activity. The paper examines public perception of the risk of disasters in this interesting socio-cultural and regional environment not already covered by existing literature. A wide national survey conducted between March and May 2012 resulted in 1,164 responses across the 13 regions of Saudi Arabia. The study showed that the majority of the participants have faith that God is in control of the world and that disasters may be a punishment from him. However, this does not hinder their desire to be prepared to cope with disasters. It also highlighted that direct experience with such disasters does not directly influence perception. The research findings lead to the emergence of a number of recommendations regarding raising awareness of hazards and the risk of disasters, including education, training, encouraging voluntary work, and improving public access to vital information resources. A requirement for research into resilience also emerges, to prepare communities to cope with disasters; this is the focus of the authors’ future research.     

Assessment of pollution sources in the southeastern of the Riyadh and its impact on the population/Saudi Arabia

The rapid growth of Riyadh—capital of Saudi Arabia—is pushing the area to more pollution and incentive for reorganization. The aim of this research is to assess air pollutants in southeast of Riyadh and detect opinion of the population about their environment. The assessment was done by analyzing 405 questionnaires, evaluating thermal band of Landsat 8, and spatial analyzing of particular matter and chemicals in 19 air samples by geostatistical tool in the ArcMap. Most of the inhabitants stated that they are suffering from bad odor, sewage leakage, and dust mainly from a cement factory. The thermal band of Landsat clarified the location of the pollution sources mainly the 1st industrial city, Yammama Cement Factory, and power plant in Farouq area. The ordinary kriging maps showed that the highest concentration of PM₁₀ (>403 μg/m³) lied to the northern and western side of the study area and caused a health issue to most inhabitants.     

Structural Setting and Kinematic Analysis of the Halaban Region,Eastern Arabian Shield,Saudi Arabia

The vorticity analysis technique was applied to measure the different lithological units,such as schist,metagranite and metavolcano-sedimentary rocks,which are present in the Halaban region.This work aims to interpret the relationship between the different lithologies and the tectonic setting,in order to elucidate the nature of kinematic analysis in the Halaban region.The kinematic analyses were applied to feldspar porphyroclasts,quartz and hornblende for twentysix samples.The kinematic vorticity number (W_m) for deformed rocks in the study area ranged from～0.6 to 0.9.The direction of the long axes for finite strain data (X axes) revealed a WNW trend with shallow dipping.The direction of the short axes for finite strain data (Z axes) were represented by vertical with associated horizontal foliation.The results of the kinematic vorticity and strain analyses are characterized by simple shear with different degrees of deformation in the Halaban region.Furthermore,our finite strain data shows no significant volume change during deformation.The subhorizontal foliation was synchronized with thrusting and deformation.Furthermore,throughout the overlying nappes,the same attitudes of tectonic contacts are observable,the nappes in the orogens being formed from simple shear deformation.     

Chemical evolution of an inland sabkha: a case study from Sabkha Matti,Saudi Arabia

Hydrogeology Journal - Sabkha Matti is a potential discharge point for regional groundwater systems in the Rub’ al Khali topographic basin of Saudi Arabia. The hydrogeochemical evolution of...     

Near-surface foundation level assessment from seismic measurements: a case study of north Jeddah City,Saudi Arabia

In this study, a comprehensive assessment on the generation mechanism, distribution characteristics, and extension rules of structure cracks was conducted by in situ monitoring and field investigation in the Chengchao Iron Mine. Structure cracks are affected by many factors, e.g., surface deformation, structure strength, occurrence position, and machine vibration. They initially occur in a structure when the strength of the structure is not enough to resist the inner strain as surface deformation increases. In contrast, increases in width and length of structure crack exert stress release in the structure and thus decrease structure deformation surrounding the crack. A great ground crack may adversely aggravate structure cracking and release the stress of surrounding rock masses. In addition, micro cracks in rock masses provide favorable conditions for the generation and extension of cracks, resulting that cracks occur in shaft walls more easily and extend towards the deeper. The initial distribution of cracks is generally consistent with such micro cracks. Subsequently, cracks in deep rock masses will extend along the strike of the mined-out area as surface deformation increases. Sensibilities to cracking of structures are changed by their different strain resistances and become stronger from bolt-shotcrete shaft, bolt-shotcrete tunnel, and brick-concrete building to brick wall. Based on distribution characteristics of cracks and wave velocity in rock masses, the overlaying strata affected by underground mining can be divided into four zones: broken zone, broken transition zone, crack generation zone, and micro deformation zone.     

U-series isotopic composition of kasolite associated with aplite-pegmatite at Jabal Sayid,Hijaz region,Kingdom of Saudi Arabia

Uranium and thorium isotopic composition of kasolite [Pb(UO₂)SiO₄-(H₂O)] from Jabal Sayid area was determined by thermal ionization mass spectrometry. Secondary electron imaging, back-scattered electron imaging, and energy dispersive spectral scans were used to investigate the mineralogical characteristics of this uranyl mineral phase. Distinct crystal faces and crystal growth of kasolite from the study area confirm mineral precipitation near the surface from the circulating groundwater. The obtained data were used to interpret the mechanism of uranium mobility in Jabal Sayid weathering profile and to construct a tentative model to explain the isotopic evolution of uranium and thorium. This model indicates that (1) uranium was leached at depth, (2) uranyl mineralization was precipitated along fractures and cavities in the host rocks during humid conditions and pluvial periods, (3) preferential leaching of ²³⁴U from uranyl mineralization by recoil processes was continuous indicative of a weakly circulating groundwater, and (4) ²³⁴U-deficiency resulted in isotopic signatures characterized by low ²³⁴U/²³⁸U and high ²³⁰Th/²³⁴U ratios. The modification pattern of these activity ratios suggests that uranyl mineralization of Jabal Sayid, most probably, has been precipitated during the same Late Quaternary pluvial periods responsible for the formation of the corresponding mineralizations in the Eastern Desert of Egypt.     

Geochemical assessment of groundwater contamination with special emphasizes on fluoride,a case study from Midyan Basin,northwestern Saudi Arabia

Water samples for chemical analyses were collected in January 2012. A total of 72 samples of groundwater were collected from 72 boreholes in the Midyan Basin, northwestern Saudi Arabia. Samples were collected in polyethylene bottles and preserved and the used analytical techniques were in accordance with the standard methods from American public health association. Geochemical analyses of the groundwater samples from Midyan Basin reveal the concentration of fluoride (F) between 0.98 and 2.1 mg/l. Other parameters, e.g, pH, EC, TDS, HCO₃, SO₄, NO₃, Cl, K, Na, Mg, and Ca have been found in a variable proportion. Among them, the concentration of EC, HCO₃, K, Na and Mg is higher than the permissible limits. According to thermodynamical considerations, most of the analysed samples are graded under-saturated with respect to calcite and fluoride, while saturation has been observed in some samples. The under-saturation could probably be attributed to low concentration of calcite and fluoride in the studied wells. Fluoride concentration shows weak positive correlation with EC, TDS, Na, Cl, and SO₄. Factors controlling the concentration of fluoride (F) in the studied samples are the area climate, water chemistry and the presence of accessory minerals in the rocks through which groundwater is circulating, besides the anthropogenic activities in the area.     

Petrology of Mantle Xenoliths from Harrat al Kishb: The Mantle beneath Western Saudi Arabia

Tertiary to Recent continental rifting and sea floor spreadingformed the Red Sea. Mantle xenoliths from the Saudi ArabianRed Sea margin provide an opportunity to study the mantle beneaththe flanks of this young ocean basin. The Harrat al Kishb mantlexenolith suite consists of Cr-diopside group spinel harzburgiteand lherzolite mantle wall rock, and a variety of pyroxenitesproduced by crystallization from mafic magmas within the mantle.The pyroxenites include two texturally distinct varieties ofCr-diopside group spinel websterites, and Al-augite group spinelpyroxenite, garnet-spinel websterite, and garnet-bearing spinelclinopyroxenite. All Harrat al Kishb xenoliths are deformedto some degree and many are recrystallized. Mineral exsolutionand zoning textures indicate reequilibration to decreasing temperatureconditions. Several xenoliths provide evidence for metasomaticprocesses in the mantle beneath western Saudi Arabia. Estimates of peridotite temperatures are 900–980?C withpressure bracketed between 13 and 19 kb. Al-augite spinel pyroxenitesyield temperatures of 1050–1070?C. Garnet-spinel websteritesyield temperatures and pressures in the range 1000–1030?C,13.8–16.5 kb. These P-T estimates show that mantle temperatures are elevatedwell above those predicted by low surface heat flow measurements.Mantle heating associated with rifting is young enough thatsurface heat flow has not yet equilibrated. The xenolith dataare consistent with a model of asthenosphere upwelling beneaththe Red Sea rift. Comparison of xenolith data with existingseismic refraction data reveals a coherent picture of the compositionof the western Saudi Arabian lithosphere.