Major flare effects on the intensity of the green corona and geomagnetic activity     

Levent Altaş 《Earth, Moon, and Planets》1989,46(2):127-134

The effects of the solar major flares indicated by the intensive radio bursts, high velocity streams or shock waves, coronal and ionospheric disturbances on the geomagnetic and coronal activities are investigated during the near the maximum phase of 21st solar cycle, in detail. The significant and the weak increases in the level of the geomagnetic and coronal activities indices were observed, respectively, after the occurrence of these events.  相似文献   

Stream flow forecasting using neuro‐wavelet technique     

Özgür Kişi 《水文研究》2008,22(20):4142-4152

This paper proposes the application of a neuro‐wavelet technique for modelling monthly stream flows. The neuro‐wavelet model is improved by combining two methods, discrete wavelet transform and multi‐layer perceptron, for one‐month‐ahead stream flow forecasting and results are compared with those of the single multi‐layer perceptron (MLP), multi‐linear regression (MLR) and auto‐regressive (AR) models. Monthly flow data from two stations, Gerdelli Station on Canakdere River and Isakoy Station on Goksudere River, in the Eastern Black Sea region of Turkey are used in the study. The comparison results revealed that the suggested model could increase the forecast accuracy and perform better than the MLP, MLR and AR models. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

A New Natural Secondary Reference Material for Garnet U-Pb Dating by TIMS and LA-ICP-MS     

Namık Aysal  Marcel Guillong  Tamara Bayanova  Mayuko Fukuyama  Nicole Leonard  İsak Yılmaz  Elif Varol  Fatma Şişman Tükel  Yusuf Kaan Kadıoğlu  Nurullah Hanilçi  Fulya Uzun  Ersin Kaygısız 《Geostandards and Geoanalytical Research》2023,47(2):297-310

Gem quality andradite-rich garnet (IUC-1), obtained from the Miocene trachyte dome near Ankara city (Turkey), has been identified as a potential natural secondary reference material for U-Pb dating. In this study, U-Pb dating was performed in five different laboratories using isotope dilution TIMS and laser ablation ICP-MS to determine the homogeneity of euhedral garnet crystals. The U-Pb ID-TIMS data for IUC-1 yielded ²⁰⁷Pb/²³⁵U and ²⁰⁶Pb/²³⁸U ages of 20.9 ± 0.4 and 20.6 ± 0.8 Ma respectively, and these values are consistent with U-Pb LA-ICP-MS analyses, in which different garnet crystals yielded ages of 20.8 ± 0.1, 20.7 ± 0.1, 20.7 ± 0.2 and 20.2 ± 0.1 Ma. An andradite (IUC-2) from the Serçeören wollastonite skarn (Turkey) can be used as a secondary reference material provided detailed imaging of the crystals is undertaken. ID-TIMS data yielded ²⁰⁷Pb/²³⁵U and ²⁰⁶Pb/²³⁸U ages of 20.4 ± 0.4 and 20.9 ± 1.0 Ma respectively, and yielded U-Pb ages on different grains of 20.5 ± 0.1, 20.7 ± 1.0, 20.8 ± 1.7 and 20.9 ± 1.6 Ma. The assigned weighted mean age of IUC-1 (20.4 ± 0.5 Ma, 2s) is proposed as a 2023 reference value. IUC-1 garnet is expected to contribute significantly to rapidly developing garnet geochronology in the near future.  相似文献   

Field reconnaissance on seismic performance of RC buildings after the January 24, 2020 Elazığ-Sivrice earthquake     

Yurdakul  Özgür  Duran  Burak  Tunaboyu  Onur  Avşar  Özgür 《Natural Hazards》2021,105(1):859-887

Natural Hazards - A moderate earthquake with a magnitude Mw of 6.8 occurred in the Sivrice district of Elaz?? Province in Eastern Turkey on January 24th, 2020. The mainshock and long-term...  相似文献   

Basin progress: active deformation analysis by tectonostratigraphic elements and geophysical methods on North Anatolian Fault System (Eastern Marmara Region,Turkey)     

Doğan  Bülent  Aşci  Metin  Karakaş  Ahmet  Pekşen  Ertan  Erener  Arzu  Çepni  Murat Selim  Yavuzyilmaz  Selin  Alahmad  Mohammad  Sertçelik  Fadime  Sertçelik  İbrahim  Kurtuluş  Cengiz 《Natural Hazards》2021,109(2):1675-1716

Natural Hazards - The Northern Branch of the North Anatolian Fault System controls and deforms the Izmit Basin and the Sapanca Lake Basin in the study area. Unlike the Sapanca Lake Basin, the...  相似文献   

Batch and column experiments to support heavy metals (Cu,Zn and Mn) in alluvial sediments     

E. Dişli 《中国地球化学学报》2010,29(4):365-374

Laboratory batch sorption and column transport experiments were performed on heterogeneous alluvial soils with a wide range of physical characteristics from wells that are located in the region between Mogan Lake and Eymir Lake, Gölba??, Ankara. The mean values for the K _d of Cu were found to be highest in clay (32550.350 L/kg) and lowest in loamy sand (18170.76 L/kg). The minimum and maximum sorption capacity values (mean values) for Zn were found to be in clay (10985.148 mg/kg) and in silty loam (8597.14 mg/kg) units, respectively. Similarly, the minimum and maximum values for Mn were found in loamy sand (4908.695 mg/kg) and clay (7587.391 mg/kg) units. The non-linear least-squares optimization code “CXTFIT” was used to determine transport parameter values by curve-fitting. The results of the column experiments demonstrate dispersivity values within the range of 0.024–1.13 cm for soil samples.  相似文献   

From Tethys to Eastern Paratethys: Oligocene depositional environments, paleoecology and paleobiogeography of the Thrace Basin (NW Turkey)     

Yeşim İslamoğlu  Mathias Harzhauser  Martin Gross  Gonzalo Jiménez-Moreno  Stjepan Coric  Andreas Kroh  Fred Rögl  Jan van der Made 《International Journal of Earth Sciences》2010,99(1):183-200

The Oligocene depositional history of the Thrace Basin documents a unique paleogeographic position at a junction between the Western Tethys and the Eastern Paratethys. As part of the Tethys, shallow marine carbonate platforms prevailed during the Eocene. Subsequently, a three-staged process of isolation started with the Oligocene. During the Early Rupelian, the Thrace Basin was still part of the Western Tethys, indicated by typical Western Tethyan marine assemblages. The isolation from the Tethys during the Early Oligocene is reflected by oolite formation and endemic Eastern Paratethyan faunas of the Solenovian stage. The third phase reflects an increasing continentalisation of the Thrace Basin with widespread coastal swamps during the Late Solenovian. The mollusc assemblages are predominated by mangrove dwelling taxa and the mangrove plant Avicennia is recorded in the pollen spectra. The final continentalisation is indicated by the replacement of the coastal swamps by pure freshwater swamps and fluvial plains during the Late Oligocene (mammal zone MP 26). This paleogeographic affiliation of the Thrace Basin with the Eastern Paratethys after ~32 Ma contrasts all currently used reconstructions which treat the basin as embayment of the Eastern Mediterranean basin.  相似文献   

Roles of hydrogeochemical evaluations in estimating protection zones of Koçpınar springs in Aksaray, central Anatolia, Turkey     

H. Elhatip  M. Afşin 《Environmental Geology》2001,40(8):1010-1016

The present study indicates estimation of protection zones of KoçpLnar springs in Aksaray area by means of hydrogeochemical methods. Relevant hydrogeochemical studies were carried out to achieve this objective. KoçpLnar springs emerge on strike-slip Hasanda<L fault set (HFS) along the Tuzgölü (Salt Lake) fault zone (TFZ) in central Anatolia. The outcrops of volcanic origin exhibit different hydrogeological properties in the study area. The hydrogeochemical evaluations of KoçpLnar springs represent good results about the available main groundwater flow systems that exist in this area. Marbles of Palaeozoic age form the main aquifer that recharges KoçpLnar springs. The CO₂ gas content of the spring waters is significantly high. Based on the ion concentrations, the water of this spring has mainly two hydrochemical facies: Ca-Mg-HCO₃ and Na-HCO₃. Although, the hydrochemical analyses showed that waters of these springs meet the drinking and irrigation water standards, the area around the springs is continuously being contaminated by both domestic and agricultural wastes. Therefore, detailed hydrogeological, hydrochemical and isotopic investigations were carried out to accurately estimate the protection zones of KoçpLnar springs. These studies showed that three main protection zones could be proposed against external pollution effects around the spring's area.  相似文献   

Sur l'importance de la diffusion élevée pendant le crépuscule     

František Link  Luděk Neužil  Igor Zacharov 《Studia Geophysica et Geodaetica》1964,8(3):274-286

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On the geomagnetic lunar variation at Istanbul     

A. Mete Işikara 《Pure and Applied Geophysics》1973,102(1):120-123

Summary The article describes lunar daily magnetic variation inH, D andZ components of the earth's magnetic field at Istanbul. Maximum occurs at 10.03 l.hr. (lunar hour) in theH component, 3.38 l.hr. in theD and 2.15 l.hr. in theZ component, during the period 1949 to 1968. Also, the seasonal variation of the lunar magnetic variation has been determined and it is seen that the variation of the phase inD andZ are opposite from the phase of the lunar variation inH, and the amplitudes of the lunar variation inH, D andZ are greatest during the northern solstice.  相似文献