Earth Fissuring and Land Subsidence in Western Saudi Arabia   总被引：4，自引：0，他引：4  

Bankher  Khalid A.  Al-Harthi  Abbas A. 《Natural Hazards》1999,20(1):21-42

The present investigation deals with the engineering geological evaluation of earth fissuring associated with land subsidence in Wadi Al-Yutamah. The investigations include surface mapping and sampling, in situ and laboratory soil testing, water well inventory, geophysical survey, and monitoring of open fissures and the level of the wadi floor.The earth fissures in the area developed as a result of land subsidence due to man-induced water level declines caused by pumping water from the wadi aquifer above a safe yield. This situation has produced a compaction of underlying unconsolidated sediments and formed hair fissures above ridges and steps of buried surface bedrock. These hair fissures enlarged later after flood erosion and possible enhancement with hydrocompaction.The wadi soil in the study area consists mainly of silt of low plasticity, low density and high void ratio and it was classified as loess like material and collapsing soil. The settlement in the area is greatly increased by excessive wetting under constant pressures. The calculated coefficients of subsidence (collapse) show that the wadi soils were considered to pose moderate problems when wetted.Monitoring of the existing open earth fissures using extensometers indicates that the width of the fissure increases after flooding or rain falls. Monitoring of the ground level using GPS techniques, shows a good relation between the declination of the water table and the subsidence of the ground of the wadi floor.  相似文献   

An efficient numerical model for incompressible two-phase flow in fractured media   总被引：1，自引：0，他引：1  

Hussein Hoteit  Abbas Firoozabadi 《Advances in water resources》2008

Various numerical methods have been used in the literature to simulate single and multiphase flow in fractured media. A promising approach is the use of the discrete-fracture model where the fracture entities in the permeable media are described explicitly in the computational grid. In this work, we present a critical review of the main conventional methods for multiphase flow in fractured media including the finite difference (FD), finite volume (FV), and finite element (FE) methods, that are coupled with the discrete-fracture model. All the conventional methods have inherent limitations in accuracy and applications. The FD method, for example, is restricted to horizontal and vertical fractures. The accuracy of the vertex-centered FV method depends on the size of the matrix gridcells next to the fractures; for an acceptable accuracy the matrix gridcells next to the fractures should be small. The FE method cannot describe properly the saturation discontinuity at the matrix–fracture interface. In this work, we introduce a new approach that is free from the limitations of the conventional methods. Our proposed approach is applicable in 2D and 3D unstructured griddings with low mesh orientation effect; it captures the saturation discontinuity from the contrast in capillary pressure between the rock matrix and fractures. The matrix–fracture and fracture–fracture fluxes are calculated based on powerful features of the mixed finite element (MFE) method which provides, in addition to the gridcell pressures, the pressures at the gridcell interfaces and can readily model the pressure discontinuities at impermeable faults in a simple way. To reduce the numerical dispersion, we use the discontinuous Galerkin (DG) method to approximate the saturation equation. We take advantage of a hybrid time scheme to alleviate the restrictions on the size of the time step in the fracture network. Several numerical examples in 2D and 3D demonstrate the robustness of the proposed model. Results show the significance of capillary pressure and orders of magnitude increase in computational speed compared to previous works.  相似文献   

Evaluation of Negative Economic-Environmental Externalities of Overextraction of Groundwater     

Mostafa Baniasadi  Mohammad Reza Zare' Mehrjordi  Hossein Mehrabi Boshrabadi  Hamid Reza Mirzaei Khalilabad  Abbas Rezaei Estakhrooye 《Ground water》2020,58(4):560-570

In recent decades, increased extraction of groundwater for human and agriculture consumption has led to a substantial drop in groundwater level in large areas of across the world. Declining groundwater levels is a serious problem in itself and has multiple economic, social, cultural, political, security-related, and environmental externalities. The negative economic-environmental externalities of overextraction of groundwater in the Orzouiyeh plain in the Kerman Province, Iran, were evaluated using methods such as replacement cost, production function, market prices, shadow price, and the value of the input marginal product. After evaluating externalities, the Positive Mathematical Programming method was used to evaluate different water policies to reduce the consumption of groundwater. The total economic losses due to the externalities were calculated to equal 2.8 U.S. million dollars. The damages caused by environmental externalities were calculated to equal 436.1 U.S. million dollars. The results related to the positive planning model show that the best policy among different options, such as deficit irrigation policy or combined policies, involves implementation of pressurized irrigation systems.  相似文献   

Experimental Investigation of Rheological Behavior and Wax Deposition of Waxy Oil–Disulfide Oil Systems     

Mansourpoor  Mojtaba  Azin  Reza  Osfouri  Shahriar  Izadpanah  Amir Abbas  Saboori  Rahmatallah 《Natural Resources Research》2019,28(4):1609-1617

Natural Resources Research - In this work, we studied the feasibility of using disulfide oil (DSO) as a solvent for wax prevention in pipelines. Several tests were carried out to determine the...  相似文献   

Monitoring hawksbill turtle nesting sites in some protected areas from the Persian Gulf     

Hesni Majid Askari  Rezaie-Atagholipour Mohsen  Zangiabadi Somaye  Tollab Mohammad Amin  Moazeni Mostaf  Jafari Hosein  Matin Mohammad Talebi  Zafarani Ghasem Ghorbanzadeh  Shojaei Maht  Motlaghnejad Abbas 《海洋学报(英文版)》2019,38(12):43-51

Iranian nesting populations of the critically endangered hawksbill turtle(Eretmochelys imbricate) are some of the most important in the Indian Ocean. In this study, four of the most important hawksbill nesting grounds in the Persian Gulf, situated within three Iranian marine protected areas, were surveyed during nesting season,including Nakhiloo, Ommolgorm and Kharko Islands and the mainland beaches of the Naiband Marine-Coastal National Park(NMCNP). We present GIS maps of these key nesting grounds and describe sand texture of key nesting zones, along with conservation recommendations. About 9.2(28.3%) out of 32.5 km of all shores surveyed in this study were used by nesting hawksbill turtles follows: Nakhiloo: 1.4 km(52% of potential nesting area);Ommolgorm: 1.94 km(40%); Kharko: 3.4 km(28%), and NMCNP: 2.46 km(18.9%). The average nesting density was calculated as 131 nests/km at Nakhiloo, 76 nests/km at Ommolgorm, 7 nests/km at Kharko, and 15 nests per km at NMCNP. Highest nesting density was observed in Nakhiloo and Ommolgorm. It is thought that high hawksbill nesting density in these islands seems likely a result of limiting adequate nesting shores rather than the size of population, and also low density in Kharko and NMCNP more related to past and current pressures and low population density. With the exception of Ommolgorm Island, sands at the nesting grounds were well sorted.Grain size indicated that female hawksbill turtles in the Iranian Persian Gulf nest in sands that are generally mixed, with mean grain size ranging from coarse sands(0.4Φ;～0.5–1 mm) to fine sands(2Φ;～0.25 mm). We provide and discuss conservation recommendations and suggestions for future.  相似文献   

Thermal evaluation of shear-free charged compact object     

S. M. Shah  G. Abbas 《Astrophysics and Space Science》2018,363(8):176

This paper is devoted to the thermal evolution of shear-free charged gravitating compact objects which undergoes exhausted its inner heat during gravitational collapse. The evaluation equations have been formulated by applying the perturbation of first order to Einstein–Maxwell equations and Catteno-type heat transportation equation. We show that the temperature gradient (induced in the system owing to external effects), sufficiently depends upon multiple of relaxation time and total time during which the gravitating system oscillates. By taking some particular examples of nuclear matter, it has been noted that at a particular value of luminosity, the change in existing thermal profile is greater corresponding to higher values of times during which a system comes to rest position.  相似文献   

A Study of Largest Active Region AR12192 of 24th Solar Cycle Using Fractal Dimensions and Mathematical Morphology     

Asma Zaffar  Abbas  Shaheen  Ansari  Muhammad Rashid Kamal 《Solar System Research》2020,54(4):353-359

Solar System Research - An active region (AR) of the sun is an area of strong magnetic field. Sunspots are frequently formed in an AR. Solar activity exhibits in the form of solar flares and...  相似文献   

Mélange development in the Neyriz region of Zagros Orogen,Iran: Record of convergence and collision in the Neotethyan Realm     

Parisa Gholami Zadeh  Mohammad Hossein Adabi  Mohammad Reza Ghassemi  Abbas Sadeghi  Safar Ali Eshraghi 《Basin Research》2020,32(6):1626-1652

Mélanges are formed by sedimentary, tectonic and diapiric processes and are generally found in collisional belts. The Zagros Orogeny provides an intriguing geological laboratory for the study of mélange-forming processes during the progressive tectonic evolution of the Neotethys Ocean. Different types of tectonic and sedimentary mélanges occur in specific structural positions within the Zagros orogenic belt in the Neyriz Region (Iran). Based on their block-in-matrix fabrics, and tectonostratigraphic positions, we differentiated 14 different mélange types, which mark different episodes of the tectonic evolution of the Neyriz Region from the Cretaceous subduction to the Miocene collision. The Cretaceous subduction stage is recorded by volcanic-sedimentary mélanges (Mv). Sedimentary mélanges characterized by megabreccia from the Cretaceous limestone (Ms1) and Eocene polymictic megabreccia (Ms2) represent epi-nappe mélanges formed during the Palaeocene–Eocene in wedge-top basins. The ophiolite emplacement in the Oligocene resulted in local extensional tectonics in the upper part of the ophiolitic nappe, and deposition of a polymictic megabreccia (Ms3, Ms4). As the final production of the Neotethys Ocean closure and the Eurasian-Arabian collision, the sedimentary mélanges characterized by different types of chaotic rock units (Ms5, Ms6, Ms7 and Ms8 facies) were developed in front of the Cretaceous–Eocene nappes due to growth of the orogenic wedge in the Miocene. Our findings indicate that the recognition and distinction of different types of mélange may provide additional constraints for a better understanding of the tectono-sedimentary evolution of the Neotethyan region.  相似文献   

Effects of Dietary Protein Level on Growth and Utilization of Protein and Energy by Juvenile Mangrove Red Snapper (Lutjanus argentimaculatus )   总被引：1，自引：1，他引：0  

Ghulam Abbas  Khalid Jamil  Rukhsana Akhtar 《中国海洋大学学报(英文版)》2005,4(1)

1Introduction The mangrove red snapper,Lutjanus argentimacu-latus(Forsskal,1775)is a carnivorous,warm-watereuryhaline fish that is considerably cultured in South-east Asia,Southern China and the Middle East(Le-ung et al.,1999;Estudillo et at.,2000;Ng et al.,2000;Catacutan et al.,2001).In Pakistan,it isknown for its good quality meat and also for its highconsumption rate.Although it fetches a premiumprice at local markets(Anonymous,2002),the in-creasing demand has generated interest towar…  相似文献   

Application of Large‐Scale Inversion Algorithms to Hydraulic Tomography in an Alluvial Aquifer          下载免费PDF全文

P. Fischer  A. Jardani  A. Soueid Ahmed  M. Abbas  X. Wang  H. Jourde  N. Lecoq 《Ground water》2017,55(2):208-218

Large‐scale inversion methods have been recently developed and permitted now to considerably reduce the computation time and memory needed for inversions of models with a large amount of parameters and data. In this work, we have applied a deterministic geostatistical inversion algorithm to a hydraulic tomography investigation conducted in an experimental field site situated within an alluvial aquifer in Southern France. This application aims to achieve a 2‐D large‐scale modeling of the spatial transmissivity distribution of the site. The inversion algorithm uses a quasi‐Newton iterative process based on a Bayesian approach. We compared the results obtained by using three different methodologies for sensitivity analysis: an adjoint‐state method, a finite‐difference method, and a principal component geostatistical approach (PCGA). The PCGA is a large‐scale adapted method which was developed for inversions with a large number of parameters by using an approximation of the covariance matrix, and by avoiding the calculation of the full Jacobian sensitivity matrix. We reconstructed high‐resolution transmissivity fields (composed of up to 25,600 cells) which generated good correlations between the measured and computed hydraulic heads. In particular, we show that, by combining the PCGA inversion method and the hydraulic tomography method, we are able to substantially reduce the computation time of the inversions, while still producing high‐quality inversion results as those obtained from the other sensitivity analysis methodologies.  相似文献