Ground and indoor radon measurements in a geothermal area

Geothermally active sites compared to a relatively passive site (no geothermal activity) contain much higher radon in the soil. As expected, the maximum soil radon content is at or near the major fracture zone where hot water emanates to the surface. Thus, buildings in geothermal sites nearby or at top of cracks that facilitate hot-water transfer to the surface may be extremely dangerous in terms of high radon concentrations and this situation may pose a big threat for the inhabitants. Controlled aeration of such high-risk buildings must be carefully and continuously conducted.     

Deep petroleum occurrences in the Lower Kura Depression, South Caspian Basin, Azerbaijan: an organic geochemical and basin modeling study

High sedimentation rates (as much as 2500 m/Ma) during Pliocene-Pleistocene, with a resultant undercompacted section as thick as 10,000 m, and lower than normal geothermal gradients are the main characteristics which have created all the means for generation and preservation of oil at deep layers in the Lower Kura Depression.Oils collected from eight different oil fields for analyses seem to have originated from a common source rock which probably is clastic, deposited in relatively subanoxic to suboxic transitional marine environment receiving low to moderate input of terrestrial organic matter.Oils from shallow (< 3000 m) and cold (< 70–80°C) reservoirs have been altered to various extent by bacterial activity.A computer-aided basin modeling study has been carried out to outline the spatial variation of the oil window and thus help in further identification of possible source rocks for the reservoired oil in the Lower Kura Depression. Results suggest that the potential hydrocarbon source horizons of the Miocene and Pliocene Red Bed Series of the so called Productive Succession are, even at depocenter areas, immature with respect to oil generation, and thus, are very unlikely to have been source rocks for the reservoired oils. However, the Oligocene-Lower Miocene Maykop rocks are marginally mature to mature depending on locality and the Eocene and older rocks are mature with respect to oil generation at all representative field locations. Oil generation commenced at the end of Pliocene and continues at present at depths between 6000 and 12,000 m.An unusually deep (> 10,000 m) oil window in the depocenter areas has been caused by the depressed isotherms due to extremely high sedimentation rates (up to 3000 m/Ma) for the last two million years. The main phase of oil generation is taking place at depths greater than what most of the wells in the study are have reached.     

An Ion Chromatography Method for the Determination of Major Anions In Geothermal Water Samples

A single-column suppressed ion chromatography technique was employed for the simultaneous determination of major and trace anions in sulfaterich groundwater samples. An analytical column, a self regenerating suppressor and sodium carbonate as the eluent were used to separate the anions. Method detection limits for the anions of interest were 10.4, 15.9, 36.8, 62, 60, 61 and 67 μg l⁻¹ for F⁻, Cl⁻, NO₂⁻, Br⁻, NO₃⁻, PO₄³⁻ and SO₄²⁻ respectively. The precision of the method was tested at five different concentration levels for each anion reference sample to evaluate the effectiveness of the method for groundwater analysis. Recovery studies were performed between two successive months by adding reference samples to the geothermal groundwater and drinking water samples. Precision was also assessed as the relative standard deviation of both repeatability (within-day) and reproducibility (between-day and different concentrations) for groundwater samples. Standard deviation and RSD values of 220 groundwater samples acquired over 8 months were evaluated. The suppressed ion chromatography technique was found to be a suitable method for determining major anions in sulfate-rich geothermal water samples.     

Water leakage from the power tunnel of Gezende Dam,southern Turkey: a case study

This study covers the investigations of the reasons of deformations and leakages in the energy tunnels of Gezende Dam constructed in 1990 for hydroelectric energy and the recommendations for treatments of the problems. Gezende Dam is located 30 km southwest of Mut county/Mersin in southern Turkey. The dam is concrete arch type with a height of 72 m. The energy tunnel with an approximate length of 9 km passes through six different geological units in age of Mesozoic to Cenozoic. After a short period of time of the operation of the tunnel, leakage has started from the section of gypsum, which is intercalated with dolomitic limestone between chainage from 5,970 to 6,840 m. The deformations have occurred in the concrete tunnel and springs have been detected at different places and times through the Ermenek Canyon since 1996. The preventive precautions of the water effect caused by groundwater effect on gypsum are as follows: (1) contact and consolidation grouting in the tunnel between chainage from 5,910 to 6,840 m, (2) removal of damage on the tunnel line, (3) reinforcement of the tunnel again, and (4) application of new concrete lining. Besides, a drainage gallery of 320 m was excavated in the 23 m lower and 15 m left part of tunnel base elevation in order to diminish the effect of groundwater in the section where the deformation occurred.     

Engineering properties of Hınıs ignimbrites and their usability as a building stone (Erzurum, Turkey)

The survival of several ancient monuments made of ignimbrites in Hınıs town (Erzurum-Anatolia), which has suffered from intense annual temperature fluctuations and strong seismic activity, can mainly be attributed to use of suitable building stones. This paper examines the usability as building stones of Middle Miocene Hınıs ignimbrites that widely outcrop in and around Hınıs town. The petrographical, geochemical, mechanical, and physical properties determined lead to categorization of the ignimbrites as four different types. The Hınıs ignimbrites contain dasite–trachy–andesite and rhyolite. Rhyolite is the strongest material whereas the other types, being more porous, are weaker, lighter, and have good heat-insulation properties. Being light (easily transportable, machinable, and workable), good heat insulators, environmentally friendly (because of natural ventilation), sufficiently elastic to sustain seismic loading in the area under study, and more cost-effective than artificial stones, Hınıs ignimbrites are certainly a preferable option for use as light building stone. These ignimbrites are not suitable for use as floor covering, however, (because of rapid abrasion) or for building structural columns (because of low strength).     

The deformation evaluation of Kızlaç T3A Tunnel (Osmaniye, Turkey)

This study covers the graphical analysis of deformation values measured in the Kızlaç T3A tunnel (Osmaniye, Turkey), which was built as a part of the Tarsus–Adana–Gaziantep Motorway Project. Excavation was performed through a sequence which was composed of sandstone–shale alternation, sandstone and dolerite dyke. Horizontal, longitudinal and settlement deformation values were optically read and recorded daily on a computer. These data were evaluated according to New Austrian Tunneling Method. Total deformation measurement, risky area determination and forecast of transitions between weak and stiff rock, stiff and weak rock were assessed as a result of deformation evaluation for tunnel stability, safety and economy.

The largest resultant deformation value (13 mm) was measured in the sandstone–shale alternation between chainage 500 and 550 m, which was highly weathered by groundwater and affected by local tectonic disturbance. The smallest deformation value was observed in a stiff dolerite dyke between 370 and 430 m, where at times the deformation values decreased to zero. In the sandstone, small resultant deformation values (2–4 mm) were also recorded. The 500–550-m interval of tunnel alignment had the highest risk for tunnel instability in the studied section but the deformation values (maximum 13 mm) were within the tolerable deformation range (10 cm). Small negative longitudinal deformation values decreasing between chainage 320 and 370 m and small positive longitudinal deformation values decreasing between 420 and 480 m indicate the sandstone–shale alternation (weak rock) and the dyke (stiff rock) and sandstone (stiff rock), and the sandstone–shale alternation with a fault gauge zone (weak rock), respectively. These longitudinal deformations needed probable to predict the lithological transitions ahead of the face, which in timely were used to determination of the tunnel support system.     

Estimation of Tsunami Run-up Height by Three Artificial Neural Network Methods

Tsunami run-up height is a significant parameter for dimemsions of coastal structures.In the present study,tsunami run-up heights are estimated by three different Artificial Neural Network (ANN) models,i.e.Feed Forward Back Propagation (FFBP),Radial Basis Functions (RBF) and Generalized Regression Neural Network (GRNN).As the input for the ANN configuration,the wave height (H) values are employed.It is shown that the tsunami run-up height values are closely approximated with all of the applied ANN methods.The ANN estimations are slightly superior to those of the empirical equation.It can he seen that the ANN applications are especially significant in the absence of adequate number of laboratory experiments.The restdts also prove that the available experiment data set can he extended with ANN simulations.This may be helpful to decrease the burden of the experimental studies and to supply results for comparisons.     

Evaluation of Plecoptera (Insecta) community composition using multivariate technics in a biodiversity hotspot

Eastern Black Sea Region of Turkey is a sub-ecoregion of the Caucasus Ecoregion, and its Plecoptera fauna is similar to fauna of Caucasus with unique endemic species of the region. The Caucasus Ecoregion is one of the “WWF Global 200 Ecoregions,” and it is also included in the list of top 25 hotspots in the World. Running water ecosystems of Eastern Black Sea sub-ecoregion are the most sensitive to land use change and global climate change. High-altitude aquatic ecosystems are more strongly threatened by global climate change in the region. Plecoptera constitute the most important part of the biodiversity of running waters in the region. Among the benthic macroinvertebrate taxa, Plecoptera is the best indicator of ecological conditions of running waters. The influence of environmental variables on the distribution of twenty Plecoptera species in running water ecosystems (headwaters, crenon, epirhithron, metarhithron) was assessed using canonical correspondence analysis. Sampling was carried out in 2009 and 2011. Eleven end groups were generated from the TWINSPAN analysis. Isoperla rhododendri, Isoperla grammatica, Protonemura bifida, Protonemura eumontana and Perla caucasica were closely related to pH, dissolved oxygen and riparian vegetation. Brachyptera transcaucasica transcaucasica, Nemoura martynovia, Nemoura taurica and Protonemura eumontana were related to Mg and Cu. The results show that the Plecoptera assemblage composition was affected by DO, pH, EC, temperature, nitrite, Ca, Mg, Fe, Cu, Zn, Al, riparian vegetation, altitude and stream width.     

Liquefaction of silts: the Adapazari criteria

Ground failures in the form of liquefaction, loss of bearing capacity and soil softening have been observed during the 1999 Marmara (Turkey) earthquake. Research to understand the failure phenomena has been carried out since the earthquakes. This paper attempts to provide explanations to the liquefaction failure of silts in seismic conditions. Findings from a large amount of data collected in the city of Adapazari on the physical and mechanical properties of soils is presented. A geomorphological map of the city has shown that there are surprising horizontal and vertical variations of the facies due to the activity of rivers in the past. Cases of liquefaction appear to have concentrated in former backswamp areas where silts and sandy silts were deposited by crevasse splays. Properties of the soils in zones of liquefaction and non-liquefaction have been determined down to a reasonable depth by measuring the average size, clay content and liquidity index as well as cone penetration resistances with porewater pressures to discover that there is significant discrepancy among those profiles susceptible to liquefaction and non-liquefying deposits. A set of “Adapazari Criteria” is proposed which is intended to improve over the “Chinese Criteria” and is simple enough to be universally applicable. This classification is similar to the existing criteria but emphasizes more on the clay content in addition to measuring the liquid limit and the liquidity index as well as the average size.     

Multi-disciplinary earthquake researches in Western Turkey: Hints to select sites to study geochemical transients associated to seismicity

Warm and hot spring water as well as soil gas radon release patterns have been monitored in the Aegean Extensional Province of Western Turkey, alongside regional seismic events, providing a multi-disciplinary approach. In the study period of 20 months, seven moderate earthquakes with M _L between 4.0 and 4.7 occurred in this seismically very active region; two earthquakes with magnitude 5.0 also occurred near the study area. Seismic monitoring showed no foreshock activity. By contrast, hydro-geochemical anomalies were found prior to these seismic events, each lasting for weeks. The anomalies occurred foremost in conjunction with dip-slip events and seem to support the dilatancy and water diffusion hypothesis. Increased soil gas radon release was recorded before earthquakes associated with strike-slip faults, but no soil radon anomalies were seen before earthquakes associated with dip-slip faults. Geochemical anomalies were also noticeably absent at some springs throughout the postulated deformation zones of impending earthquakes. The reason for this discrepancy might be due to stress/strain anisotropies.