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11.
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. 相似文献
12.
Clay deposits in Oltu-Narman basins (Erzurum, northern Turkey) have been studied to determine their engineering properties
and to evaluate their uses for geotechnical applications. These deposits are concentrated in two different stratigraphic horizons
namely the Late Oligocene and the Early Miocene sequences. Clay-rich fine-grained sedimentary units are deposited in shallow
marine and lagoonar mixed environments. Their clay minerals originated by the alteration of Eocene calc-alkaline island-arc
volcanics, preferably from pyroclastics (trachite and andesite flow), which form the basement for the Oltu depression. Smectite
group clay minerals are found abundant in clay deposits. The experimental results show that the clay soils have high plasticity
behaviors and low hydraulic conductivity properties. The optimum water content, the free swell, and the swelling pressure
of clay samples decreased and the maximum dry unit weight of clay samples increased under high temperature. Consequently,
it is concluded that the expanding of clay soils is an important soil problem that cannot be avoided in the significant parts
of Oltu city and its villages. However, the soils of clay-rich layers in the outcrops-section of clay deposits can be successfully
used to build compacted clay liners for landfill systems and to construct vertical and horizontal barriers for protection
of ground water and for preventing soil pollution in geotechnical applications. 相似文献
13.
Crucial to most landslide early warning system (EWS) is the precise prediction of rainfall in space and time. Researchers are aware of the importance of the spatial variability of rainfall in landslide studies. Commonly, however, it is neglected by implementing simplified approaches (e.g. representative rain gauges for an entire area). With spatially differentiated rainfall information, real-time comparison with rainfall thresholds or the implementation in process-based approaches might form the basis for improved landslide warnings. This study suggests an automated workflow from the hourly, web-based collection of rain gauge data to the generation of spatially differentiated rainfall predictions based on deterministic and geostatistical methods. With kriging usually being a labour-intensive, manual task, a simplified variogram modelling routine was applied for the automated processing of up-to-date point information data. Validation showed quite satisfactory results, yet it also revealed the drawbacks that are associated with univariate geostatistical interpolation techniques which solely rely on rain gauges (e.g. smoothing of data, difficulties in resolving small-scale, highly intermittent rainfall). In the perspective, the potential use of citizen scientific data is highlighted for the improvement of studies on landslide EWS. 相似文献
14.
Utilization of red mud as a stabilization material for the preparation of clay liners 总被引：3，自引：0，他引：3
Red mud is a waste material generated by the Bayer Process widely used to produce alumina from bauxite throughout the world. Approximately, 35% to 40% per ton of bauxite treated using the Bayer Process ends up as red mud waste. Because of storing issues, the waste negatively affects the environment. To solve this problem, it is essential to investigate different uses for red mud waste. The potential use of red mud for the preparation of stabilization material is presented in this study. This study examines the effects of red mud on the unconfined compressive strength, hydraulic conductivity, and swelling percentage of compacted clay liners as a hydraulic barrier. The test results show that compacted clay samples containing red mud and cement–red mud additives have a high compressive strength and decreased the hydraulic conductivity and swelling percentage as compared to natural clay samples. Consequently, it is concluded that red mud and cement–red mud materials can be successfully used for the stabilization of clay liners in geotechnical applications. 相似文献