Hydrological considerations for dam siting in arid regions: a Saudi Arabian study     

ZEKAI ŞEN  KHALID AL-SUBA'I 《水文科学杂志》2013,58(2):173-186

Abstract

In any dam siting study in arid regions, rainfall records, runoff measurements and their greatest magnitudes are very important. Unfortunately, the data are scarce and, therefore, empirical approaches and charts obtained from similar regions in other parts of the world are necessary for complete applications. The lack of observed data presents the major problem for runoff modelling in arid regions. These regions have characteristically high rainfall intensity and consequent flash floods with large amounts of sediments. Occurrence of rainfall is sporadic, both temporally and spatially, which makes the interpretation of the rainfall-runoff relationship quite difficult. Flood estimations play a significant role in dam siting from the point of view of water availability. This paper presents the basic calculations of floods and sediment amounts that are necessary in dam siting and construction in an arid area by considering the southwestern part of the Kingdom of Saudi Arabia.  相似文献   

Gold and Silver Prospection Using Magnetic,Radiometry and Microgravity Methods in the Kışladağ Province of Western Turkey     

Ö. A. Ercan  Aysel Şeren  Ali Elmas 《Resource Geology》2014,64(1):25-34

The study area lies in the K??lada? province of western Turkey. The site has an approximate dimension of 1.5 to 2 km north‐south length and 3 km east‐west width. Combined methods from the fields of geology, geochemistry and geophysics were applied to elucidate the regional geologic framework and identify favorable environs for mineralization. There are a few volcanic hills in the center of the K??lada? caldera, which is actually a field of interest. Magnetics (M), Magnetic Total Field Gradient (Mg), Radiometry (Ra), Microgravity (MG) and Microgravity Gradient (MGG) methods were used to prospect the terrains and boundaries of gold and silver deposition in the area. The observed mineralized zones are characterized by low magnetization, low radiation, and high density contrast. Such zones appear to exist outside and beneath a magnetized cap rock. The locations of proposed drill holes were determined with varying depths. Following completion of geophysical and geochemical exploration, an open cut mine with a yearly production rate of about 5 to 6 tons of gold minerals at depths varying between 50 to 225 m has been operational.  相似文献   

The South Marmara Fault     

Xavier Le Pichon  Caner İmren  Claude Rangin  A. M. Celâl Şengör  Muzaffer Siyako 《International Journal of Earth Sciences》2014,103(1):219-231

We use about 800 km of multichannel exploration seismic reflection profiles of the seventies as well as the results of three drill holes that penetrated the sedimentary cover down to the Upper Cretaceous basement to describe a continuous gently curvilinear, south-concave zone of deformation about 10 km wide that extended over the whole southern shelf of the Sea of Marmara from the Gulf of Gemlik to the Dardanelles Straits in Lower Pliocene time, about 4 Ma. We call this zone of deformation the South Marmara Fault (SMF) system and propose that the SMF was then a branch of the dextral North Anatolian Fault. This branch passed to the north of the Marmara Island Eocene block and thus had a south-facing concavity. This curvature resulted in a significant component of shortening in the western part of the fault. The SMF was deactivated at the end of Lower Pliocene, about 3.5 Ma, except for its easternmost branch between the Gulf of Gemlik and ?mral? Island where about 5 mm/year of dextral motion is still occurring today.  相似文献   

Layer-parallel shortening and related structures in zones undergoing active regional horizontal extension     

A. M. Celâl Şengör  Erdin Bozkurt 《International Journal of Earth Sciences》2013,102(1):101-119

Folds and thrust faults formed by layer-parallel shortening coaxial with extensional structures such as normal dip-slip faults and ductile necking structures with orthorhombic fabric symmetry are usual, but little-recognised structures formed within normal dip-slip shear zones bounding rifts. They are generated because of the shear distribution in a zone of progressive deformation and may be later extended and disrupted depending on which part of the strain ellipsoid they may be located. We here describe folds and thrust faults from the southern margin of the Ala?ehir Rift in western Turkey as an opportunity to discuss the properties of pure extension–related structures formed by layer-parallel shortening. Such structures are more commonly generated during the early stages of rifting, when deformation rates are slow and the shear zones broader than those forming later in the life of a rift when strain rates are usually higher. Such structures have commonly been mistaken for witnesses documenting regional episodes of shortening rather than as integral parts of the extensional structures forming rifts. Not all layer-parallel shortening-related structures therefore indicate regional shortening. We plead that hasty statements concerning the meaning of geological structures at all scales be avoided before a thorough understanding of bulk strains that have affected a region are properly understood.  相似文献   

Evaluating the anthropogenic and geologic impacts on water quality of the Eğirdir Lake, Turkey     

Şehnaz Şener  Ayşen Davraz  Remzi Karagüzel 《Environmental Earth Sciences》2013,70(6):2527-2544

E?irdir Lake is the second largest fresh water lake with 482 km² surface area of Turkey. The lake is an indispensable water source for our country and region because of available water capacity and usage aims such as drinking-irrigation water, tourism, and fishing. However, especially contaminants located in the E?irdir Lake catchment affect the lake water quality negatively in times. Therefore, determination of the water quality of the lake has quite importance for region human health and sustainable usage of the lake. The major factors that control the quality of the E?irdir Lake water are agricultural activities in the basin, water–rock interaction, and domestic and industrial wastes. This study investigates the anthropogenic and geologic impact originated from pollution sources and water–rock interaction in the lake watershed basin to the E?irdir Lake water quality. For this purpose, geological, hydrogeological, and hydrological properties of the lake basin with point and nonpoint pollution sources were investigated. To determine the water quality of the lake, 48 water samples were collected especially from locations representing effects of pollutants in May and October 2009. The analysis results were compared with maximum permissible limit values recommended by World Health Organization and Turkish drinking water standards. The contents of all chemical and physical parameters are higher in dry periods than wet period, and water pollution was observed at discharge points of the streams into the lake. Also, pH, turbidity, potassium, chemical oxygen demand, ammonium, aluminum, iron, and lead concentrations were found to be above drinking water standards.  相似文献   

Strategic groundwater resources planning in arid regions     

Zekai Şen  Saleh A. Al Sefry  Saleh A. Al Ghamdi  Wahib A. Ashi  Wael A. Bardi 《Arabian Journal of Geosciences》2013,6(11):4363-4375

A strategic approach is presented for future groundwater reservoir planning in arid regions where the evaluation of groundwater resources is restricted by scarcity of rainfall, data paucity, restrictive and unrepresentative methodologies, weak economies, almost nonexisting management and optimization programs, frequent groundwater quality variables along short distances, etc. This paper explains the necessary steps in preparing an effective strategic planning program that is expected to provide all the necessary data for identifying alternative solution scenarios especially in arid regions. It is shown on the basis of available scarce data that the risk model of these factors appears as the logarithmic normal probability distribution. The basic decision variables in groundwater storage and recharge planning are furnished with application to Wadi Fatimah in the western central part of the Kingdom of Saudi Arabia along the Red Sea coast. The approach given in this paper provides a basic example for future groundwater reservoir strategic use and management studies in the Kingdom in particular and in any part of the arid regions of the world, in general.  相似文献   

The Çubukludağ graben,south of İzmir: its tectonic significance in the Neogene geological evolution of the western Anatolia     

Can Ş. Genç  Şafak Altunkaynak  Zekiye Karacık  Metin Yazman  Yücel Yılmaz 《Geodinamica Acta》2013,26(1-3):45-55

Abstract

Field studies on the Neogene successions in south of ?zmir reveal that subsequent Neogene continental basins were developed in the region. Initially a vast lake basin was formed during the early-Middle Miocene period. The lacustrine sediments underwent an approximately N-S shortening deformation to the end of Middle Miocene. A small portion of the basin fill was later trapped within the N-S-trending, fault-bounded graben basin, the Çubukluda? graben, opened during the Late Miocene. Oblique-slip normal faults with minor sinistral displacement are formed possibly under N–S extensional regime, and controlled the sediment deposition. Following this the region suffered a phase of denudation which produced a regionwide erosional surface suggesting that the extension interrupted to the end of Late Miocene–Early Pliocene period. After this event the E–W-trending major grabens and horsts of western Anatolia began to form. The graben bounding faults cut across the Upper Miocene–Pliocene lacustrine sediments and fragmented the erosional surface. The Çubukluda? graben began to work as a cross garden between the E–W grabens, since that period. © 2001 Éditions scientifiques et médicales Elsevier SAS  相似文献   

Frequency-Dependent Attenuation of Coda Waves in the Crust in Southwest Anatolia (Turkey)     

Şakir Şahin  Mutlu Çinar 《Pure and Applied Geophysics》2014,171(7):1203-1217

The attenuation of coda waves in the earth’s crust in southwest (SW) Anatolia is estimated by using the coda wave method, which is based on the decrease of coda wave amplitude in time and distance. A total of 159 earthquakes were recorded between 1997 and 2010 by 11 stations belonging to the KOERI array. The coda quality factor Q _c is determined from the properties of scattered coda waves in a heterogeneous medium. Firstly, the quality factor Q ₀ (the value of Q _c at 1 Hz.) and its frequency dependency η are determined from this method depending on the attenuation properties of scattered coda waves for frequencies of 1.5, 3.0, 6.0, 8.0, 12 and 20 Hz. Secondly, the attenuation coefficients (δ) are estimated. The shape of the curve is controlled by the scattering and attenuation in the crustal volume sampled by the coda waves. The average Q _c values vary from 110 ± 15 to 1,436 ± 202 for the frequencies above. The Q ₀ and η values vary from 63 ± 7 to 95 ± 10 and from 0.87 ± 0.03 to 1.04 ± 0.09, respectively, for SW Anatolia. In this region, the average coda Q–f relation is described by Q _c = (78 ± 9)f ^0.98±0.07 and δ = 0.012 km^?1. The low Q ₀ and high η are consistent with a region characterized by high tectonic activity. The Q _c values were correlated with the tectonic pattern in SW Anatolia.  相似文献   

Multi-disciplinary earthquake researches in Western Turkey: Hints to select sites to study geochemical transients associated to seismicity     

Sedat İnan  Kadriye Ertekin  Cemil Seyis  Şakir Şimşek  Furkan Kulak  Aynur Dikbaş  Onur Tan  Semih Ergintav  Rahşan Çakmak  Ahmet Yörük  Muhiddin Çergel  Hakan Yakan  Hüseyin Karakuş  Ruhi Saatçilar  Zafer Akçiğ  Yıldız İravul  Bekir Tüzel 《Acta Geophysica》2010,58(5):767-813

Warm and hot spring water as well as soil gas radon release patterns have been monitored in the Aegean Extensional Province of Western Turkey, alongside regional seismic events, providing a multi-disciplinary approach. In the study period of 20 months, seven moderate earthquakes with M _L between 4.0 and 4.7 occurred in this seismically very active region; two earthquakes with magnitude 5.0 also occurred near the study area. Seismic monitoring showed no foreshock activity. By contrast, hydro-geochemical anomalies were found prior to these seismic events, each lasting for weeks. The anomalies occurred foremost in conjunction with dip-slip events and seem to support the dilatancy and water diffusion hypothesis. Increased soil gas radon release was recorded before earthquakes associated with strike-slip faults, but no soil radon anomalies were seen before earthquakes associated with dip-slip faults. Geochemical anomalies were also noticeably absent at some springs throughout the postulated deformation zones of impending earthquakes. The reason for this discrepancy might be due to stress/strain anisotropies.  相似文献   

Adsorption Performance and Mechanism in Binding of Azo Dye by Raw Bentonite     

Erdal Eren 《洁净——土壤、空气、水》2010,38(8):758-763

The adsorption behavior of methyl orange (MO) from aqueous solution onto raw bentonite (RB) sample was investigated as a function of parameters such as pH, inorganic anion, contact time, and temperature. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms. Langmuir adsorption capacity was found to be 34.34 mg/g at pH 4.0. The pseudo‐first‐order, pseudo‐second‐order kinetic, and the intra‐particle diffusion models were used to describe the kinetic data. The values of the energy (E_a), enthalpy (ΔH^≠), and entropy of activation (ΔS^≠) were calculated as 38.62 kJ/mol, 36.04 kJ/mol, and ?150.05 J/mol K, respectively, at pH 4.0.  相似文献