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371.
The attenuation of seismic waves reflects the elastic nature of the media within which the waves propagate. In this study, we calculate the Coda-Q(Q_c), frequency dependence(η), Vp/Vs and Poisson's(υ) ratios by using 2621 vertical component seismograms generated by 987 earthquakes recorded by 13 seismic stations in Eastern Anatolia, and creat a 2-D seismic tomographic Q_c model for the region. The obtained model provides significant information for exploring the boundaries of adjacent tectonic units within the upper crust and interpreting their dynamic characteristics. The 2-D Q_c model and the other parameters are consistent with the seismotectonic features of Eastern Anatolia. Highly heterogeneous Q_c values are observed in the study area dividing it into north-south directed bands of low and high attenuation. The highest η values were obtained beneath the northwestern and eastern parts of the study region. Clear, high and low υ values are obtained in the western and eastern parts of the study area, respectively. The spatial variations in the measured parameters are consistent with many geophysical observations including low Pn velocities, efficient Sn blockage, high heat flow, and widespread volcanism. Different upper crustal thicknesses and inhomogeneous stress distribution along the East and North Anatolian Fault Zones may also contribute to the observed heterogeneities. 相似文献
372.
A re-evaluation of the reprocessed seismic reflection data was made for the investigation of the presumed western continuation of the North Anatolian Fault (NAF) in the Aegean and mapping geometries of active faults in the Aegean Sea. Seismic data collected and processed by various national and international companies were selected from the data archives and they were reprocessed after stacking to bring them to the same processing and signal-to-noise ratio standards. The total length of the selected lines is 8000 km. We investigated the character of active faulting in the North Aegean Sea using seismic reflection data. Moreover, the relations of active faults with earthquakes were examined using earthquake fault plane solutions (FPS). We show that the active faults are dominantly normal in character in the NNE Aegean where FPS for earthquakes with M>5 indicate strike-slip movements along these faults. We propose a simple mechanism that potentially explains this inconsistency. Active normal faults are oriented in a NE–SW direction in alignment with the SW escape motion of the Anatolian block in this region and this orientation facilitates instantaneously strike-slip movements along these otherwise normal faults. 相似文献
373.
Summary Degree-days as a measure of accumulated temperature deviations from a base temperature have many practical applications in
various human related activities such as home cooling, heating, plant growth in agriculture and power generation in addition
to energy requirement. Long temperature records are necessary for their reliable estimations at given stations. In this paper,
degree-day measure has been applied to monthly temperature records for systematically changed base temperature values from
− 25 °C to + 35 °C with 5 °C increments at 255 meteorology stations in Turkey. The results are represented in the form of
spatial degree-day distribution maps, which are then related to various climatic, meteorological and topographic features
of Turkey. For instance, free surface water bodies in forms of surrounding seas, lakes and rivers insert retardation in the
expansion of heating degree-days over large regions. On the other hand, cold air penetration from polar regions in the northeastern
Turkey originating from Siberia appears at moderate base temperature heating degree-days.
Received August 20, 1998 Revised June 21, 1999 相似文献
374.
Çağatay M. N. Görür N. Alpar B. Saatçılar R. Akkök R. Sakınç M. Yüce H. Yaltırak C. Kuşcu I. 《Geo-Marine Letters》1998,18(1):1-9
The Gulf of Saros is an Upper Miocene transtensional basin in NW Anatolia, formed by the interaction between the North Anatolian
Fault and the N-S extensional tectonic régime of the Aegean. The present configuration of the basin evolved mainly during
the Plio-Quaternary under the increased activity of the North Anatolian Fault. During the late Miocene-late Quaternary, no
sedimentation took place on the shelves. After this long hiatus, an important change in tectonic style about 0.2 Ma BP allowed
sedimentation to resume in the gulf.
Received: 14 February 1997 / Revision received: 12 November 1997 相似文献
375.
376.
Toxic effects of five commonly used pesticides on the biomass of a municipal activated sludge system were determined on the basis of the reduction in the oxygen uptake rate (OUR) and specific oxygen uptake rate (SOUR). Toxicity levels of the selected pesticides were determined by employing a modified OECD 209 (Organisation for Economic Cooperation and Development) method which was performed as batch experiments using a respirometer. Copper sulphate (CuSO4 · 5 H2O), copper oxychloride (Cu2Cl(OH)3), copper calcium oxychloride (CaCu3Cl2(OH)6) as copper‐based pesticides and chlorsulphuron (C12H12ClN5O4S), 2,4‐dichlorophenoxyacetic acid (2,4‐D) (C8H6Cl2O3) as synthetic organic pesticides were selected for the experiments. The EC50 values were determined to be 78, 249 and 281 mg/L for CuSO4 · 5 H2O, Cu2Cl(OH)3 and CaCu3Cl2(OH)6, respectively. Corresponding values for C12H12ClN5O4S and 2,4‐D were 860 and 3664 mg/L, respectively. Results indicated that toxicity effects of copper‐based pesticides were higher than that of synthetic organic pesticides. CuSO4 · 5 H2O was found to exert the highest toxicity among the copper‐based pesticides, whereas, C12H12ClN5O4S was determined to be the most toxic among the organic pesticides on activated sludge biomass. 相似文献
377.
Natural Hazards - Located in the Mediterranean basin, one of the world’s leading places in terms of forest fires, Turkey is one of the countries where forest fires are experienced very often... 相似文献
378.
Ramazan Atıcı 《Astrophysics and Space Science》2018,363(11):231
The Total Electron Content (TEC) prediction performances of the empirical IRI model and IRI-PLAS model were investigated by comparing the GPS-based TEC values provided by the IONOLAB group. TEC values were obtained on equinox (March 21 and September 23) and solstice (June 21, and December 21) days in low (2009), medium (2012) and high (2015) solar activity periods at Istanbul, Turkey. The prediction performances of the models were statistically analyzed based on the differences between the GPS-TEC and the empirical models, considering the maximum and minimum deviations, the correlation analysis and the root mean square error (RMSE). As a result of the investigation, it is seen that the empirical models have similar predictive performances when the plasmaspheric effects are neglected, and the IRI-PLAS estimations are generally a little closer to the observed GPS-TEC values than all options of IRI-2016 model. Also, it can be said that “IRI2001”, one of the IRI-2016’s “topside” options, can make better predictions than other options and “IG” solar proxy option of IRI-PLAS model is a more appropriate option than the others in TEC calculations over Istanbul, Turkey. 相似文献