Investigation of the nature of slip surface using geochemical analyses and 2-D electrical resistivity tomography: a case study from Lapseki area, NW Turkey     

Ahmet Evren Erginal  Beyhan Öztürk  Yunus Levent Ekinci  Alper Demirci 《Environmental Geology》2009,58(6):1167-1175

The nature and subsurface structure of the slip surface of a landslide was studied on the basis of geochemical analyses and 2-D electrical resistivity tomography (ERT) survey. Head scarp and lateral slip surfaces of the landslide marked by clear slickensided shear planes were composed of the average amounts of clayey silt (32.5%) and sand (67.5%). Energy dispersive X-ray spectroscopy (EDX) data revealed the enrichment of Si (23.24%), Fe (12.2%), Al (9.51%) and C (8.34%) in the elemental composition of the disturbed slip surface. From X-ray diffractometry (XRD) data, six main clay types were determined, such as Volkonskoite, Halloysite, Ferrosilite, Saponite, Illite and Nontronite. The ERT survey displayed that the landslide developed as a reactivation on the upper part of an old landslide body.  相似文献   

Evaluation of andesite source as armourstone for a rubble mound breakwater (Hisarönü, Turkey)     

Utku Ahmet Ozden  Tamer Topal 《Environmental Earth Sciences》2009,59(1):39-49

Black Sea coast line is a hazardous region especially in winter due to the dominant wave action. Therefore, rubble mound breakwaters protected with armourstone used as ship shelters are vital structures especially for the fishermen. The deterioration of the armourstone with time in the form of abrasion and disintegration may result in the failure of the breakwater. In this study, the properties of the armourstone taken from an andesite quarry and used in the Hisarönü rubble mound breakwater were studied both in field and laboratory in order to assess their qualities and long-term durabilities. Based on the in situ observations and laboratory tests, the andesite is found to be generally marginal rock. CIRIA/CUR, RDI_s, RERS and Wet-Dry strength ratio classifications are in good agreement with the in situ observations and the results of the laboratory tests. However, RDI_d, Average Pore Diameter and Saturation Coefficient classifications cannot correctly predict long-term durability of the armourstone. Field studies reveal that block size of the andesite in the quarry increases with depth due to the increase in spacing of the cooling joints of the rock.  相似文献   

Interpretation of magnetic anomalies of dikes using correlation factors   总被引：1，自引：0，他引：1  

Ibrahim Kara  Mustafa Özdemir  F. Ahmet Yüksel 《Pure and Applied Geophysics》1996,147(4):777-788

The magnetic anomaly due to a buried dike consists of the sum of two easily separated elementary functions. These functions, which have simple symmetry, are called even and odd functions. The correlation factors (r _0,1 for the even andr _0,2 for the odd function) between least-squares residual anomalies from even and odd functions are computed. Correlation values are used to determine the depth to the top and the half-width of the dike. The method also includes the determination of the index parameter and the amplitude coefficient. The validity of the method is tested against a theoretical and a field example where the parameters of the latter were determined by other investigators in comparing the results.  相似文献   

Nonlinear meta-models for conceptual seakeeping design of fishing vessels     

Ayla Sayli  Ahmet Dursun Alkan  Onur Ganiler 《Ocean Engineering》2010,37(8-9):730-741

The scope of this paper is to develop the nonlinear meta-models for seakeeping behaviour, considering the fishing vessels. These models are intended to be inserted either in a multiattribute design selection process or in a comprehensive multiobjective optimization procedure. For this purpose, seakeeping data of fishing vessels in regular head waves are used to develop meta-models of transfer functions of heave, pitch and vertical acceleration by nonlinear analysis. A home-made software considers two databases; the first is composed by the ship dimensions and coefficients of fishing vessels, and the second is their ship motion data obtained by employing a strip-theory calculation. The meta-models are proposed to predict the vertical motion characteristics for given ranges of speed and wave length during the concept design stage. The independent variables are hull size (Δ), main dimensions (L, B, T), and some hydrostatic parameters (C_WP, C_VP, LCB, LCF, etc.). The results estimated by the software show good correspondences with the ones achieved by direct computations. The study provides additional insight on the influence of hull form parameters on seakeeping performance of small vessels having form properties and parametric range corresponding to the investigated vessels.  相似文献   

Landslide Susceptibility Mapping and Evaluation along a River Valley in China   总被引：1，自引：0，他引：1  

LI Yanrong  Adnan AYDIN  XIANG Xiqiong  JU Nengpan  ZHAO Jianjun  Ahmet OZBEK 《《地质学报》英文版》2012,86(4):1022-1030

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Environmental problems at the Nevşehir (Kozakli) geothermal field,central Turkey     

Suzan Pasvanoğlu  Ahmet Güner  Fatma Gültekin 《Environmental Earth Sciences》2012,66(2):549-560

The Kozakli–Nev?ehir geothermal field extends a long a NW–SE direction at SE of the Centrum of Kozakli. The area is not rugged and average elevation is 1,000 m. The Kozanözü Creek flows towards north of the area. In the Kozakli thermal Spa area, thermal waters are manifested along a valley with a length of 1.5 km and 200 m width. In this resort some hot waters are discharged with no use. The thermal water used in the area comes from wells drilled by MTA. In addition, these waters from wells are also utilized by hotels, baths and motels belonging to City Private Management, Municipality and private sector. The measured temperature of Kozakli waters ranges from 43–51°C in springs and 80–96°C in wells. Waters are issued in a wide swampy area as a small group of springs through buried faults. Electrical conductivity values of thermal spring and well waters are 1,650–3,595 μS/cm and pH values are 6.72–7.36. Kozakli cold water has an electrical conductivity value of 450 μS/cm and pH of 7.56. All thermal waters are dominated by Na⁺ and Cl–SO₄ while cold waters are dominated by Ca⁺² and HCO₃ ^?. The aim of this study was to investigate the environmental problems around the Kozakli geothermal field and explain the mechanisms of karstic depression which was formed by uncontrolled use of thermal waters in this area and bring up its possible environmental threats. At the Kozakli geothermal field a sinkhole with 30 m diameter and 15 m depth occurred in January, 17th 2007 at the recreation area located 20 m west of the geothermal well which belongs to the government of Nev?ehir province. The management of the geothermal wells should be controlled by a single official institution in order to avoid the creation of such karstic structures affecting the environment at the source area.  相似文献   

Validation of the Meteosat Second Generation (MSG) fire monitoring product using ground observations over Turkey     

Ibrahim Sönmez  Ahmet Emre Tekeli  Erdem Erdi  Fatih Demir  Murat Arslan 《Arabian Journal of Geosciences》2014,7(8):3389-3398

Validation of the active fire monitoring (FIR) product from Spinning Enhanced Visible and Infrared Imager sensor of Meteosat Second Generation satellite is performed over Turkey. Ground truth data from the Ministry of Environment and Forestry for the years 2007, 2008, and 2009 is used by taking the active fire months of April–September into consideration. The contingency tables are obtained on a monthly basis and categorical statistics of probability of detection (POD) and false alarm rate (FAR) are derived. The results are introduced for each subclass, namely probable, possible, and combined cases. The highest POD amounts of 8.5, 1.93, and 9.4 % are obtained for the possible, probable, and combined cases, respectively, with the lowest FAR amounts of 70.9, 4.5, and 86.1 % for the same categories. FIR product validation with respect to predefined burnt area thresholds is introduced in the second part of the study in order to investigate burnt area effect in active fire detection. Increasing POD values with respect to burnt area amount is obtained with relatively higher values in probable than possible type. On the other hand, FAR variation is observed to be not correlated with the burnt area amount.  相似文献   

Mapping of total nitrogen,available phosphorous and potassium in Amik Plain,Turkey   总被引：1，自引：0，他引：1  

Veli Uygur  Ahmet Irvem  Sema Karanlik  Rifat Akis 《Environmental Earth Sciences》2010,59(5):1129-1138

Soil nitrogen, phosphorous, and potassium concentrations accurately revealed spatial distribution maps and site-specific management-prone areas through inverse distance weighting (IDW) method in the Amik Plain, Turkey. Spatial mapping of soil nitrogen, phosphorous, and potassium is a very severe need to develop an economically and environmentally sound soil management plans. The objectives of this study were (a) to map spatial variability of total N, available P, and exchangeable-K content of Amik Plain’s soils and (b) to locate problematic areas requiring site specific management strategies for the nutrient elements. Spatial analyses of Kjeldhal-N, Olsen-P, and exchangeable-K concentrations of the soils were performed by the IDW method. Mean N content for surface soils (0–20 cm) was 1.38 g kg⁻¹, available P was 28.19 kg ha⁻¹ and exchangeable-K was 690 kg ha⁻¹ with the differences between maximum and minimum being 7.63 g N kg⁻¹, 242 kg P ha⁻¹, and 2,082 kg K ha⁻¹. For the surface soil, site-specific management-prone areas of Kjeldahl-N, Olsen-P, and exchangeable-K for “low and high + very high” classes were found to be 20.1–17.8%, 24.7–10.0%, and 4.1–39.6%, respectively. Consequently, lands with excessive nutrient elements require preventive-leaching practices, whereas nutrient-poor areas need fertilizer applications in favor of increasing plant production.  相似文献   

How to stir a revolution as a reluctant rebel: Rudolf Trümpy in the Alps     

A. M. Celâl Şengör  Daniel Bernoulli 《International Journal of Earth Sciences》2011,100(5):899-936

Rudolf Trümpy (1921–2009) was one of the great Alpine geologists of the twentieth century and an influential figure in the international geological community. He played a dominant role in the change of opinion concerning the Alpine evolution by showing that normal faulting dominated the early development of the Alpine realm from the Triassic to the early Cretaceous. This provided a convenient model for later plate-tectonic interpretations of collisional mountain belts. His further recognition of strike-slip faulting during all stages of the Alpine evolution presaged the realisation that the Alps were not built by a simple open-and-shut mechanism. Trümpy was educated during an intellectual lull, a time when simplistic models of the earth behaviour inherited from the middle of the nineteenth century became prevalent under the influence of a close-minded, positivist approach to geological problems. This period, which we term the Dark Intermezzo, lasted from about 1925 to 1965. The grand syntheses of Suess and Argand which preceded this period were viewed from this narrow angle and consequently misunderstood. It was thought that earth history was punctuated by global orogenic events of short duration taking place within and among continents and oceans whose relative positions had remained fixed since the origin of the planet. These views, summarised under the term ‘fixism’, were developed when the ocean floors were almost totally unknown. When data began coming in from the post World War II oceanographic surveys, the world geological community was slow to receive and digest them. Trümpy followed these developments closely, realising that his work was important in placing the geology of the mountain belts within the emerging, new theoretical framework. He adopted the position of a critic and emphasised where detailed knowledge of the Alps, unquestionably the best known mountain belt in the world, supported and where it contradicted the new ideas. His voice was listened to carefully and subsequent developments have shown his critique to have been prescient. It is regrettable that he did not publish some of the theoretical criticisms he communicated to his colleagues during scientific meetings and informal conversations. His hesitance in becoming involved in theoretical arguments in geology may have stemmed partly from his scientific upbringing during the Dark Intermezzo and partly because he genuinely believed that he was better off sticking to what he thought he knew for sure. He nevertheless stressed that it is important for geologists ‘to dream’. It is often said about teachers that one should do what they say, not what they do. In Trümpy’s case, it was the opposite. Both scientifically and as a human being, he was a most admirable man.  相似文献   

Applications of hybrid genetic algorithms in seismic tomography     

Pantelis Soupios  Irfan Akca  Petros Mpogiatzis  Ahmet T. Basokur  Constantinos Papazachos 《Journal of Applied Geophysics》2011,75(3):479-489

Almost all earth sciences inverse problems are nonlinear and involve a large number of unknown parameters, making the application of analytical inversion methods quite restrictive. In practice, most analytical methods are local in nature and rely on a linearized form of the problem equations, adopting an iterative procedure which typically employs partial derivatives in order to optimize the starting (initial) model by minimizing a misfit (penalty) function. Unfortunately, especially for highly non-linear cases, the final model strongly depends on the initial model, hence it is prone to solution-entrapment in local minima of the misfit function, while the derivative calculation is often computationally inefficient and creates instabilities when numerical approximations are used. An alternative is to employ global techniques which do not rely on partial derivatives, are independent of the misfit form and are computationally robust. Such methods employ pseudo-randomly generated models (sampling an appropriately selected section of the model space) which are assessed in terms of their data-fit. A typical example is the class of methods known as genetic algorithms (GA), which achieves the aforementioned approximation through model representation and manipulations, and has attracted the attention of the earth sciences community during the last decade, with several applications already presented for several geophysical problems.In this paper, we examine the efficiency of the combination of the typical regularized least-squares and genetic methods for a typical seismic tomography problem. The proposed approach combines a local (LOM) and a global (GOM) optimization method, in an attempt to overcome the limitations of each individual approach, such as local minima and slow convergence, respectively. The potential of both optimization methods is tested and compared, both independently and jointly, using the several test models and synthetic refraction travel-time date sets that employ the same experimental geometry, wavelength and geometrical characteristics of the model anomalies. Moreover, real data from a crosswell tomographic project for the subsurface mapping of an ancient wall foundation are used for testing the efficiency of the proposed algorithm. The results show that the combined use of both methods can exploit the benefits of each approach, leading to improved final models and producing realistic velocity models, without significantly increasing the required computation time.  相似文献