Soil characterization of Tınaztepe region (İzmir/Turkey) using surface wave methods and nakamura (HVSR) technique

To determine the shear wave velocity structure and predominant period features of T?naztepe in ?zmir, Turkey, where new building sites have been planned, active–passive surface wave methods and single-station microtremor measurements are used, as well as surface acquisition techniques, including the multichannel analysis of surface waves (MASW), refraction microtremor (ReMi), and the spatial autocorrelation method (SPAC), to pinpoint shallow and deep shear wave velocity. For engineering bedrock (V _s > 760 m/s) conditions at a depth of 30 m, an average seismic shear wave velocity in the upper 30 m of soil (AV_s30) is not only accepted as an important parameter for defining ground behavior during earthquakes, but a primary parameter in the geotechnical analysis for areas to be classified by V _s30 according to the National Earthquake Hazards Reduction Program (NEHRP). It is also determined that Z1.0, which represents a depth to V _s = 1000 m/s, is used for ground motion prediction and changed from 0 to 54 m. The sediment–engineering bedrock structure for T?naztepe that was obtained shows engineering bedrock no deeper than 30 m. When compared, the depth of engineering bedrock and dominant period map and geology are generally compatible.     

Performance and Sustainability of District-Scale Ground Coupled Heat Pump Systems

This study proposes a solution to the problem of maintaining the performance and sustainability of district-scale, cooling-dominated ground coupled heat pump (GCHP) systems. These systems tend to overheat because heat dissipates slowly in relation to the size of the borefields. To demonstrate this problem, a 2000-borehole field is considered at a district-scale GCHP system in the Upper Midwest, US. The borefield’s ground and fluid temperature responses to its design heating and cooling loads are simulated using computational fluid dynamics implemented by applying the finite volume method. The ground temperature is predicted by applying the thermal loads uniformly over the borefield and simulating heat dissipation to the surrounding geology through conduction coupled with advection due to groundwater flow. The results show that a significant energy imbalance will develop in the ground after the first few years of GCHP operation, even with high rates of groundwater flow. The model presented in this study predicts that the temperature at the center of the borefield will reach 18 °C after 5 years and approximately 50 °C after 20 years of operation in the absence of any mitigation strategies. The fluid temperature in the boreholes is then simulated using a single borehole model to estimate the heat pump coefficient of performance, which decreases as the modeled system heats up. To balance the energy inputs/outputs to the ground—thus maintaining the system’s performance—an operating scheme utilizing cold-water circulation during the winter is evaluated. Under the simulated conditions, this mitigation strategy carries the excess energy out of the borefield. Therefore, the proposed mitigation strategy may be a viable measure to sustaining the operating efficiency of cooling-dominated, district-scale borefields in climates with cold winters.     

Determination of areas vulnerable to pollution in a karstic river basin in Turkey via a decision support system based on DRASTIC,SWAT and isotopes analysis

Determination of areas vulnerable to water pollution in river basins helps to generate appropriate water management protection plans. This study aims to define areas vulnerable to pollutants in a data-scarce karstic river basin in Turkey by using a holistic approach integrating the Soil and Water Assessment Tool (SWAT), the DRASTIC framework, and selected isotopes within a decision support system based on a geographic information system to delineate vulnerable areas. DRASTIC was used to show groundwater vulnerability to pollutants. The concentrations of isotopes ¹⁸O, ²H, and ³H in groundwater were used to define the vulnerable areas of the karst region. SWAT was utilized to show watershed vulnerability to pollutants in shallow aquifers. The recharge rate parameter in DRASTIC was obtained from SWAT. This methodological approach was applied to the Yuvacık Dam Basin in Kocaeli, part of the Marmara River Basin, as it is a good example of a karstic watershed. According to this study, each approach provides different vulnerabilities when applied separately. The final map obtained from the integrated approach shows that drinking water supplies in the northeast and northwest parts of the basin are highly vulnerable to pollution. All the karst spring catchments and areas near the basin outlet are highly vulnerable. Moreover, across all water samples taken across the basin, those exhibiting the highest concentrations in nitrate were all found in the areas mapped as highly vulnerable. The methodology was validated by analyzing nitrate concentration in 22 groundwater and surface-water samples.

     

High spatial resolution analysis of ferromanganese concretions by LA-ICP-MS†

A procedure was developed for the determination of element distributions in cross-sections of ferromanganese concretions using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The effects of carrier flow rates, rf forward power, ablation energy, ablation spot size, repetition rate and number of shots per point on analyte intensity were studied. It is shown that different carrier gas flow rates are required in order to obtain maximum sensitivities for different groups of elements, thus complicating the optimisation of ICP parameters. On the contrary, LA parameters have very similar effects on almost all elements studied, thus providing a common optimum parameter set for the entire mass range. However, for selected LA parameters, the use of compromise conditions was necessary in order to compensate for relatively slow data acquisition by ICP-MS and maintain high spatial resolution without sacrificing the multielemental capabilities of the technique. Possible variations in ablation efficiency were corrected for mathematically using the sum of Fe and Mn intensities. Quantification by external calibration against matrix-matched standards was successfully used for more than 50 elements. These standards, in the form of pressed pellets (no binder), were prepared in-house using ferromanganese concentrates from a deep-sea nodule reference material as well as from shallow-marine concretions varying in size and having different proportions of three major phases: aluminosilicates, Fe- and Mn-oxyhydroxides. Element concentrations in each standard were determined by means of conventional solution nebulisation ICP-MS following acid digestion. Examples of selected inter-element correlations in distribution patterns along the cross-section of a concretion are given.     

Landslide risk assessment and management by decision analytical procedure for Dereköy, Konya, Turkey

The Dereköy landslide threatening the town of Dereköy, Konya, Turkey is investigated in order to assess and manage the associated risk. Dereköy town, located 12 km west of Konya city center, which is the second largest city in central Anatolia, has been extending due to the demand for new settlement places in Konya for the last decade. As most of the town is situated on the slopes of Meram river valley, on which the slope movements are observed, the risk of landslide has been increasing due to these new settlements. In this study, the landslide risk in Dereköy is assessed by following the so-called decision analytical procedure. The risk is defined by multiplication of hazard and consequences of the hazard. The hazard, which is the probability of slope failure, is computed by using the first-order second-moment (FOSM) method. The possible consequences of a landslide in Dereköy are analyzed and their costs are assessed relative to each other. A decision tree for choosing among the possible alternatives for reducing the risk is constructed in order to manage the risk.     

Earthquake behavior of steel cushion-implemented reinforced concrete frames

The earthquake performance of vulnerable structures can be increased by the implementation of supplementary energy-dissipative metallic elements. The main aim of this paper is to describe the earthquake behavior of steel cushion-implemented reinforced concrete frames (SCI-RCFR) in terms of displacement demands and energy components. Several quasi-static experiments were performed on steel cushions (SC) installed in reinforced concrete (RC) frames. The test results served as the basis of the analytical models of SCs and a bare reinforced concrete frame (B-RCFR). These models were integrated in order to obtain the resulting analytical model of the SCI-RCFR. Nonlinear-time history analyses (NTHA) were performed on the SCI-RCFR under the effects of the selected earthquake data set. According to the NTHA, SC application is an effective technique for increasing the seismic performance of RC structures. The main portion of the earthquake input energy was dissipated through SCs. SCs succeeded in decreasing the plastic energy demand on structural elements by almost 50% at distinct drift levels.     

Impact of acid sulfate soils on the geochemistry of rivers in south-western Finland

Large areas of acid sulfate (AS) soils are located along the coastal plains of Finland, and previous studies have shown that after reclamation they release extreme quantities of metals to watercourses in mid-western and northern Finland. In this study on streams of south-western Finland, where little information about AS soils is available, these soils were found to exhibit the same pattern of elevated metal- and sulfate concentrations as in the notorious AS soil landscapes of mid-western Finland. Meteorologically/hydrologically driven temporal variations of these elements were great in the most affected streams. There were also significant positive implications regarding future environmental work; AS soils in the highlighted region were found to cause sudden temporal influxes of acidic water only in the most affected streams, indicating that the overburden and soils of the area discharge well buffered water. Moreover, it was indicated that the high (less toxic) metal concentrations are largely caused by erosion of suspended phyllosilicates (<0.45 μm) from farmland rather than by AS soils.     

Petrographic and geochemical features of the dolostones at the Gölboğazı Formation (Upper Devonian), Southwest Konya,Turkey

This paper describes the occurrence of dolostone and the mechanism of dolomitization of the Upper Devonian Gölbo?az? Formation in the allochthonous Taurus Mountains Alada? unit in Turkey. The Upper Devonian Gölbo?az? Formation carbonates, with dominant ostracod-bearing mudstone and wackestone, formed tidal and subtidal environments, and some of these rocks were dolomitized from shallow to deep burial. On the basis of the field, the petrographic and geochemical features, four different replaceable and cement dolostone phases have been recognized. The replacive dolostones contain (1) very fine to fine crystalline planar-s dolostone (df1), (2) medium to coarse crystalline planar-s to planar-e dolostone (df2), (3) coarse to very coarse crystalline non-planar-a dolostone (df3), and (4) coarse to very coarse crystalline planar dolostone cement (df4). The replacive dolostones are disordered to moderate the ordered and calcium-rich. They are non-stoichiometric and have 46–59 mol% CaCO₃ and 41–54 mol% MgCO₃ total contents. The df1 dolostones have MgCO₃ contents of 41–54 mol%, the df2 dolostones have 41–53 mol%, the df3 dolostones have 49 mol%, and the df4 dolostones have 49–50 mol%, respectively. The Gölbo?az? dolostones have δ¹⁸O values of ?9.44 to ?2.20‰ Vienna Pee Dee Belemnite (VPDB) and δ¹³C values of ?1.58 to +2.52 VPDB. Sr, Na, Mn, and Fe concentrations of replacive dolostones are 74–184, 148–593, below detection level (bdl)–619, and 1049–9233 ppm, respectively. The petrographic and geochemical data demonstrate that the replacive dolostones occurred prior to the chemical compaction at shallow to intermediate burial depths from Late Devonian seawater and/or seawater lightly modified by water–rock interaction process and later recrystallized by basinal brines at increasing burial depths and temperature. The North American Shale Composite-normalized rare earth element values of both limestone and dolostone show very similar rare earth element patterns characterized by slightly or considerably negative cerium (Ce) anomalies and a clear depletion in all rare earth element species. The dedolomitization observed in the Gölbo?az? Formation is thought to occur by the oxidizing effect of the meteoric water in the shallow burial environment during the telodiagenesis.     

Impact of the Atatürk Dam Lake on Agro-Meteorological Aspects of the Southeastern Anatolia Region,Turkey

In this study, the spatial and temporal impacts of the Atatürk Dam on agro-meteorological aspects of the Southeastern Anatolia region have been investigated. Change detection and environmental impacts due to water-reserve changes in Atatürk Dam Lake have been determined and evaluated using multi-temporal Landsat satellite imageries and meteorological datasets within a period of 1984–2011. These time series have been evaluated for three time periods. Dam construction period constitutes the first part of the study. Land cover/use changes especially on agricultural fields under the Atatürk Dam Lake and its vicinity have been identified between the periods of 1984–1992. The second period comprises the 10-year period after the completion of filling up the reservoir in 1992. At this period, Landsat and meteorological time-series analyses are examined to assess the impact of the Atatürk Dam Lake on selected irrigated agricultural areas. For the last 9-year period from 2002 to 2011, the relationships between seasonal water-reserve changes and irrigated plains under changing climatic factors primarily driving vegetation activity (monthly, seasonal, and annual fluctuations of rainfall rate, air temperature, humidity) on the watershed have been investigated using a 30-year meteorological time series. The results showed that approximately 368 km² of agricultural fields have been affected because of inundation due to the Atatürk Dam Lake. However, irrigated agricultural fields have been increased by 56.3% of the total area (1552 of 2756 km²) on Harran Plain within the period of 1984–2011.