Preliminary investigation of underground settlements of Nevşehir Castle region using 2.5-D electrical resistivity tomography: Cappadocia,Turkey

The Nev?ehir Castle region located in the middle of Cappadocia with approximately cone shape is investigated for the existence of an underground city using the geophysical method of electrical resistivity tomography. Underground cities are commonly known to exist in Cappadocia. The current study has obtained important clues that there may be another one under the Nev?ehir Castle region. Several 2.5-D resistivity profiles totaling approximately 4 km in length surrounding the Nev?ehir Castle are measured to determine the distribution of electrical resistivities under the study area. Several high resistivity anomalies with a depth range 8–20 m are discovered to associate with a systematic void structure beneath the Nev?ehir Castle. Because of the high-resolution resistivity measurement system currently employed, we were able to isolate the void anomalies from the embedding structure. Using 3-D visualization techniques, we show the extension of the void structure under the measured profiles.     

The transition from the Soviet system to a market economy as a cause of instability in the Estonian coastal fisheries sector

This study analyzes how overall changes in political and economic life during the last decade have affected the Estonian coastal fishery of the Baltic Sea. At the beginning of the nineties, the opportunity to export fish to the European market emerged. Opening of this new market resulted in rapidly increasing pressure on fish stocks. Some of the most important coastal fishery resources were over-fished because of high export market demand coupled with insufficient resource management and ineffective control and enforcement mechanisms. The costs associated with fishery have grown much more than the first-buyer prices. Additionally, dynamic development of the Estonian economy has resulted in substantial increases in earnings in other economic sectors and therefore the relative wealth of fishermen has steadily declined. This has resulted in increasing social problems. In conclusion, countries in transition may encounter serious difficulties in the fisheries sector, arising from privatization and economic reforms, which may affect the fisheries even years after the establishment of new ruling principles.     

NAPL source zone depletion model and its application to railroad-tank-car spills

We developed a new semi-analytical source zone depletion model (SZDM) for multicomponent light nonaqueous phase liquids (LNAPLs) and incorporated this into an existing screening model for estimating cleanup times for chemical spills from railroad tank cars that previously considered only single-component LNAPLs. Results from the SZDM compare favorably to those from a three-dimensional numerical model, and from another semi-analytical model that does not consider source zone depletion. The model was used to evaluate groundwater contamination and cleanup times for four complex mixtures of concern in the railroad industry. Among the petroleum hydrocarbon mixtures considered, the cleanup time of diesel fuel was much longer than E95, gasoline, and crude oil. This is mainly due to the high fraction of low solubility components in diesel fuel. The results demonstrate that the updated screening model with the newly developed SZDM is computationally efficient, and provides valuable comparisons of cleanup times that can be used in assessing the health and financial risk associated with chemical mixture spills from railroad-tank-car accidents.     

Vibration characteristics of a suspension bridge under traffic and no traffic conditions

This paper presents the variations of vibration under different traffic conditions on the Fatih Sultan Mehmet suspension bridge in Istanbul, Turkey.The main intention is to determine the vibration amplifications under heavy-traffic as opposed to no-traffic conditions. This is the first study in this particular area that has been performed on this bridge, over which an average of 200,000 cars pass daily. Two full-scale ambient vibration surveys were carried out on two different days to determine the response of the bridge to diverse traffic conditions. Initial measurements were taken as the bridge experienced heavy stress conditions caused by rush-hour traffic. Secondary measurements were recorded after closing the bridge to traffic. The data were analyzed to gauge the vibration effects of heavy-traffic conditions on the bridge and to determine the effects of different traffic conditions on the free vibration characteristics of the bridge. The analyses were performed utilizing different amplification methods. Results show that there are important differences in the amplifications of the vibration amplitudes. Especially heavy-traffic on the bridge causes the vibration response of the bridge to be intensified in comparison to no-traffic conditions. Additionally, predominant frequencies are shifted as a direct result of traffic load acting on the bridge. Even more importantly and is probably analogous for all long-span bridges, is the fact that any movement causing vibration on the bridge is carried and amplified along its length. These significant amplifications indicate the important effect of varying traffic loads and how the bridge responds to the diverse movements it experiences. Copyright © 2011 John Wiley & Sons, Ltd.     

Crushed recycled glass as a filter medium and comparison with silica sand

The objective of this work was to evaluate crushed recycled glass as a medium for rapid filtration. In the first part of this work, physical and hydraulic characteristics of the glass medium were studied. In the second part, pilot scale inline filtration experiments were carried out using raw waters from three different water sources. Two physically identical filter columns were operated in parallel in all the experiments. One filter contained a silica sand medium that is widely used in Turkey, whereas the other filter contained crushed recycled glass. Experiments were repeated five times as follows: (i) Without the use of a coagulant, (ii–iii) with 5 mg/L and 10 mg/L of alum, and (iv–v) with 5 mg/L and 10 mg/L of ferric chloride. Turbidity, particle counts, and head losses were measured and compared as functions of time. The following were observed: (1) Provided that a coagulant was used, the filter containing crushed glass produced effluent turbidities and particle counts similar to those obtained with the sand filter. (2) The crushed glass medium generated both a smaller clean‐bed head loss and smaller clogging head losses than those of the sand filter. It is concluded that crushed glass shows significant promise as an alternative to silica sand in rapid filtration.     

Ambient noise levels and characterization in Aegean region,Turkey

We assessed the ambient noise level in the Aegean region and analyzed its diurnal variation and its relation to the earthquake detection capability of the Aegean Region Seismic Network (ARSN). We prepared probability density functions (PDFs) for 19 broadband stations in the Aegean region operated by the Earth and Marine Sciences Institute (EMSI) of the Marmara Research Center (MRC) of the Turkish Scientific Research Council (TÜB?TAK). The power spectral densities (PSDs) used to construct PDFs for each station were computed for the periods between ~?0.02 and 180 s. In addition, we generated noise map of the Aegean region for different periods using the PDFs to assess the origin of the noise. We analyzed earthquake activity in the region and found that there are more local events recorded at night than during the day for each station. This difference is strongly related to diurnal variation of background noise level for the period range mostly covering the frequency range for the local events. We observed daytime noise level ~?15 to 20 dB higher than that at the nighttime in high frequencies for almost all stations caused by its proximity to settled areas and roads. Additionally, we observed a splitting peak within the Double Frequency (DF) microseism band; it showed a clear noise increase around the short period DF band at all the stations, decreasing inland. This peak may be related to sea waves locally generated in the Aegean Sea. We also identified a prominent increase related to marble saw companies in some stations’ noise PDFs.     

Simulation of a 3D submerged jet flow around a pile

The submerged 3D turbulent jet flow behavior around a pile on a rigid bed and on a scoured bed was studied experimentally and numerically. ADV was used to obtain the jet velocity distributions and Realizable k–ε turbulence model was used for the prediction of flow field around a pile. The jet flow area was three-dimensional and thus numerical model was a three-dimensional model. The numerical results were used to predict the velocity close to the pile and bed shear stress on the bed. In general, the results indicated that the flow field was also in agreement with the findings of previous experiments in literature and the related principles in the subject area. The experimental results demonstrated that Acoustic Doppler Velocimeter (ADV) measurements were almost identical with the Realizable k–ε turbulence model results for turbulence intensity I=10%.     

Character of active faulting in the North Aegean Sea

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.     

Responses of the stratified flows to their driving conditions—A field study

The Bosphorus is oceanographically very complicated two-layer stratified strait where denser water from the Marmara Sea flows towards North under the lighter water which is frequently flowing from the Black Sea towards South. The water level difference between both ends of the Bosphorus varies seasonally within the range of ?0.2 and 0.6 m. The seasonal variability depends mainly on the water level changes in the adjacent basins related to the hydrological cycle, short-term changes in the atmospheric pressure and the wind characteristics. These variations together with the depth and alignment of the cross section along the strait dominate the spatial and temporal variations and sometimes sharp changes in the flow pattern in three dimensions. Although these hydrodynamic conditions are critical for all marine and hydraulic works along the Bosphorus, there was not continuous long-term measurement for a sufficient time span in the strait for detailed evaluation of the current climate. An extensive site surveying work including current, wind, pressure and water level measurements was carried out between September 2004 and January 2006 in relation to the design and construction requirements of the Bosphorus Tube Crossing Project. In this study, the characteristics of stratified flow in the Bosphorus Strait and their relation to local and regional, short- and long-term changes in the meteorological parameters are studied by using the measurement data and the results are discussed comparatively.     

Geological evolution of the Gulf of Saros,NE Aegean Sea

 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