Application of Chebyshev theorem to data preparation in landslide susceptibility mapping studies:an example from Yenice(Karabük,Turkey) region

Landslide database construction is one of the most crucial stages of the landslide susceptibility mapping studies. Although there are many techniques for preparing landslide database in the literature, representative data selection from huge data sets is a challenging, and, to some extent, a subjective task. Thus, in order to produce reliable landslide susceptibility maps, data-driven, objective and representative database construction is a very important stage for these maps. This study mainly focuses on a landslide database construction task. In this study, it was aimed at building a representative landslide database extraction approach by using Chebyshev theorem to evaluate landslide susceptibility in a landslide prone area in the Western Black Sea region of Turkey. The study area was divided into two different parts such as training (Basin 1) and testing areas (Basin 2). A total of nine parameters such as topographical elevation, slope, aspect, planar and profile curvatures, stream power index, distance to drainage, normalized difference vegetation index and topographical wetness index were used in the study. Next, frequency distributions of the considered parameters in both landslide and nonlandslide areas were extracted using different sampling strategies, and a total of nine different landslide databases were obtained. Of these, eight databases were gathered by the methodology proposed by this study based on different standard deviations and algebraic multiplication of raster parameter maps. To evaluate landslide susceptibility, Artificial Neural Network method was used in the study area considering the different landslide and nonlandslide data. Finally, to assess the performances of the so-produced landslide susceptibility maps based on nine data sets, Area Under Curve (AUC) approach was implemented both in Basin 1 and Basin 2. The best performances (the greatest AUC values) were gathered by the landslide susceptibility map produced by two standard deviation database extracted by the Chebyshev theorem, as 0.873 and 0.761, respectively. Results revealed that the methodology proposed by this study is a powerful and objective approach in landslide susceptibility mapping.     

Spatial and temporal variation of suspended sediment concentration versus turbidity in the stream Harşit Watershed,NE Turkey

Suspended sediment related studies based on direct measurements for Turkish rivers and streams are very few for various reasons such as cost, time, or fewer operational sediment gauging stations, and thus the researchers tend to look for indirect methods. Turkey is a developing country and in need of many investments, which resulted in engineering and management modifications in its river and stream systems. This paper investigates the spatial and temporal variations of suspended sediment concentration (SSC, mg/L) versus turbidity (NTU) in the stream Har?it watershed having a length of the main branch at 143 km and catchment area of 3,280 km², Eastern Black Sea Basin of Turkey. Subsequently, the effect of the all kinds of anthropogenic activities was evaluated, namely, dam operation, levee construction, municipal wastewater discharge, sand–gravel mining on SSC, and turbidity in the watershed. In situ turbidity monitoring and water sampling studies were semimonthly conducted at ten stations from March 2009 to February 2010. On a semimonthly basis, it was revealed that SSC and turbidity values having significant correlation varied spatially and temporarily. The municipal wastewater discharge from the city of Gümü?hane together with the decreasing flow rate revealed itself with a significant increase in the turbidity and SSC, especially in the summer months. Torul Dam having a reservoir volume of 168 hm³ could trap 78.6 % of the SSC and could remove 66.6 % of the turbidity, thanks to its long hydraulic residence time; however, Kürtün Dam released the suspended sediment as a result of its sluiceway tunnel operation. Sand–gravel mining activities between the last two stations severely affected the water quality by increasing the SSC and turbidity.     

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.     

Effects of mining subsidence on masonry buildings in Zonguldak hard coal region in Turkey

Gallerias are the underground constructed results of mining. As these space in underground layers collapse, horizontal and vertical ground movements occur and movement which may reach the earth’s surface are known as mining subsidence. The result of underground displacement may cause surface ground movement which can be detrimental to masonry buildings especially in hard coal regions. Thorough familiarity with general and regional characteristics of an affected area can assist reduction of the effects. Zonguldak and the nearby settlement area, with a population of 300,000, constitute the centre of a hard coal basin where extensive mining has a history extending through 160 years. Mining constitutes the main economic activity in this region, and consequently influences every aspect of life. This study’s intent is to identify the effects of mining subsidence on masonry buildings in the mining area of Kozlu, Zonguldak, Turkey and illustrate them with selected images of damaged masonry buildings. Also included are satellite and mining galleria images.     

Determination of radioactivity levels in Akhisar,Gördes,Gölmarmara and Sindirgi regions,Western Turkey

In this study, radioactivity measurements in the environment of Akhisar, Gölmarmara, Gördes and Sindirgi regions in Western Turkey were investigated in order to evaluate the implications of any excess radioactivity in the environment of geological formation. The radioactivity concentrations of ⁴⁰K, ²³⁸U and ²³²Th radionuclides in the soil samples were measured by a NaI(Tl) gamma spectrometer system, and the radium activity concentrations in the water samples were also analyzed by an ZnS(Ag) alpha counter by the collector chamber method. The radioactivity of ⁴⁰K, ²³⁸U and ²³²Th in soils ranged 2.80–2,347.77, 9.90–256.19 and 9.66–106.53 Bq kg^?1, respectively. The activity of ²²⁶Ra in the water samples ranged from 0.03 Bq L^?1 (0.89pCi/L) to 0.80 Bq L^?1 (21.58pCi/L). In addition, the external terrestrial gamma dose rate in air (nGy h^?1), annual effective dose rate (mSv year^?1) and radium equivalent activity (Bq kg^?1) were calculated and compared with international standard values.     

Geomorphological features and weathering of the Southern Submassif of the Menderes Massif (SW Turkey)

The Southern Submassif crops out in the SW of Turkey. This submassif consists of mostly large feldspar-bearing orthogneisses and to a lesser extent tourmaline-orthoclase-plagioclase-, quartz-, muscovite-, and biotite-bearing leucogranites. The orthogneiss forms domed bald hills. The leucogranites crop out (approximately 2 km²) in the southeastern lowland of the hill. Those units show various geomorphological features that are typically reported in granitoids. Many studies about the Menderes Massif are related with petrography and metamorphic history. The geomorphological features are not taken into consideration. Field observation, thin section analysis, joint set-foliation measurements, and Schmidt Hammer value determination were done in this study. The pillar structures (castellated and domed types) are among larger structures observed on flanks of the domed bald hill. Geomorphological features such as weathering pits, tafoni, honeycomb structures, polygonal cracks, flared slopes, exfoliation, and boulders are observed. The metamorphism causes mineral alignments that affect the strength of the rock. The studied rocks have high strength in perpendicular direction to foliation. The complex tectonic history caused developments of several joint sets. Differences in mineral strength (e.g., high in quartz, low in biotite and feldspar) increase weathering effect. Underground water percolation through the fractures weakens the rock and causes subsurface weathering. After exhumation, disintegrated materials are stripped off, and then flared slopes, polygonal cracks, and pillar structures are exposed. Surface weathering by wind and water increases the weathering effects and gives rise to a formation of rounded rock edges called spheroidal weathering. Contrary to other granitoid areas, the metamorphism promotes the formation of geomorphological features in the study area.     

Long-term trend analysis using discrete wavelet components of annual precipitations measurements in Marmara region (Turkey)

The purpose of this study is to determine the possible trends in annual total precipitation series by using the non-parametric methods such as the wavelet analysis and Mann-Kendall test. The wavelet trend (W-T) analysis is for the first time presented in this study. Using discrete wavelet components of measurement series, we aimed to find which periodicities are mainly responsible for trend of the measurement series. We found that some periodic events clearly affect the trend of precipitation series. 16-yearly periodic component is the effective component on Bal?kesir annual precipitation data and is responsible for producing a real trend founded on the data. Also, global wavelet spectra and continuous wavelet transform were used for analysis to precipitation time series in order to clarify time-scale characteristics of the measured series. The effects of regional differences on W-T analysis are checked by using records of measurement stations located in different climatic areas. The data set spans from 1929 to 1993 and includes precipitation records from meteorological stations of Turkey. The trend analysis on DW components of the precipitation time series (W-T model) clearly explains the trend structure of data.     

A statistical analysis of seismo-ionospheric TEC anomalies before 63 <Emphasis Type="Italic">M</Emphasis><Subscript>w</Subscript> ≥ 5.0 earthquakes in Turkey during 2003–2016

In this study, pre-seismic and post-seismic total electron content (TEC) anomalies of 63 M_w?≥?5.0 earthquakes in Turkey (36°–42°N, 26°–45°E) were statistically investigated. The largest earthquake that occurred in Turkey during 2003–2016 is the M_w 7.1 Van earthquake on October 23, 2011. The TEC data of epicenters is obtained from CODE-GIM using a simple 4-point bivariate interpolation. The anomalies of TEC variations were determined by using a quartile-based running median process. In order to validate GIM results, we used the GPS-TEC data of available four IGS stations within the size of the Van earthquake preparation area. The anomalies that are detected by GIM and GPS-TEC show a similar pattern. Accordingly, the results obtained with CODE-GIM are reliable. The statistical results show that there are not prominent earthquake precursors for M_w?≤?6.0 earthquakes in Turkey.     

Selective Preconcentration of Trace Amounts of Cu(II) With Surface‐Imprinted Multiwalled Carbon Nanotubes

In this study, a new sorbent is synthesized using surface imprinting technique. Cu(II)‐imprinted multiwalled carbon nanotube sorbent (Cu(II)‐IMWCNT) is used as the solid phase in the solid‐phase extraction method. After the preconcentration procedure, Cu(II) ions are determined by high‐resolution continuum source atomic absorption spectrometry. A total of 0.1 mol L^?1 ethylenediaminetetraacetic acid (EDTA) is used to remove Cu(II) ions from the sorbent surface. The optimum experimental conditions for effective preconcentration of Cu(II), parameters such as pH, eluent type and concentration, flow rate, sample volume, sorbent capacity, and selectivity are investigated. The synthesized solid phase is characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The maximum adsorption capacities of Cu(II)‐IMWCNT and non‐imprinted solid phases are 270.3 and 14.3 mg g^?1 at pH 5, respectively. Under optimum experimental conditions for Cu(II) ions, the limit of detection is 0.07 μg L^?1 and preconcentration factor is 40. In addition, it is determined to be reusable without significant decrease in recovery values up to 100 adsorption–desorption cycles. Cu(II)‐IMWCNT have a high stability. To check the accuracy of the developed method, certified reference materials, and water samples are analyzed with satisfactory analytical results.