Geophysical Assessment of Groundwater Potential: A Case Study from Mian Channu Area,Pakistan

An integrated study using geophysical method in combination with pumping tests and geochemical method was carried out to delineate groundwater potential zones in Mian Channu area of Pakistan. Vertical electrical soundings (VES) using Schlumberger configuration with maximum current electrode spacing (AB/2 = 200 m) were conducted at 50 stations and 10 pumping tests at borehole sites were performed in close proximity to 10 of the VES stations. The aim of this study is to establish a correlation between the hydraulic parameters obtained from geophysical method and pumping tests so that the aquifer potential can be estimated from the geoelectrical surface measurements where no pumping tests exist. The aquifer parameters, namely, transmissivity and hydraulic conductivity were estimated from Dar Zarrouyk parameters by interpreting the layer parameters such as true resistivities and thicknesses. Geoelectrical succession of five‐layer strata (i.e., topsoil, clay, clay sand, sand, and sand gravel) with sand as a dominant lithology was found in the study area. Physicochemical parameters interpreted by World Health Organization and Food and Agriculture Organization were well correlated with the aquifer parameters obtained by geoelectrical method and pumping tests. The aquifer potential zones identified by modeled resistivity, Dar Zarrouk parameters, pumped aquifer parameters, and physicochemical parameters reveal that sand and gravel sand with high values of transmissivity and hydraulic conductivity are highly promising water bearing layers in northwest of the study area. Strong correlation between estimated and pumped aquifer parameters suggest that, in case of sparse well data, geophysical technique is useful to estimate the hydraulic potential of the aquifer with varying lithology.     

Modified perspective cylindrical map projection

Some of the famous cylindrical projections are defined by a geometric process that is based on the perspective. This process can be imagined as a semitransparent sphere wrapped by a tube, secant, or tangent, with the same center; then all features of the sphere surface are projected onto the tube surface by light rays from a source in the equatorial plane. Just by changing the light source’s position and tube’s diameter, different maps can result. In every cylindrical perspective projections, distortions are functions of latitude only, thus, the value of distortion is fixed along a parallel (or a small circle). Therefore, distortion isograms are parallels (or small circles), symmetrical in relation of the equator. Consequently, it is suitable for territories having narrow band shape, extended by the equator (or an oblique equator). The proposed projection in this paper introduces another possible adjustment in cylindrical projections, in which axis of cylinder does not pass through the center of the sphere. This may satisfy case, where territories have a closed curve shape. By comparing the distribution of distortions in other famous perspective cylindrical projections (Lambert, stereographic, and central), with that in the proposed modified perspective cylindrical projection, it was found that distribution of area distortion in the proposed projection can be considered better than others. Therefore, in relation to area representation, the modified perspective cylindrical projection can be considered suitable for mapping regions, having shape close to an ellipse.     

Tectonic geomorphology of the Kemalpaşa Basin and surrounding horsts,southwestern part of the Gediz Graben,Western Anatolia

The Kemalpa?a Basin is one of the Quaternary basins in Western Anatolia and represents the south-western branch of the Gediz Graben system in this extensional province. This basin has been formed under the NNE–SSW trending extensional tectonic regime. It is bounded by a major fault, the Kemalpa?a Fault, in the south and it is bounded by a number of downstepping faults, called as Spilda?? Fault Zone, in the north. Both margin-bounding faults of the Kemalpa?a Basin are oblique-slip normal faults. In order to better understand the activities of these faults, we investigated the tectonic geomorphology of the Kemalpa?a Basin and interpreted the effect of tectonic activity on the geomorphological evolution using geomorphic markers such as drainage basin patterns, facet geometries and morphometric indices such as hypsometric curves and integral (HI), basin shape index (B_s), valley floor width-to-height ratio (V_f) and mountain front sinuosity (S_mf). The morphometric analysis of 30 drainage basins in total and mountain fronts bounding the basin from both sides suggests a relatively high degree of tectonic activity. The mountain front sinuosity (S_mf) generally varies from 1.1 to 1.3 in both sides of the basin suggesting the active fronts and facet slopes (12°–32°) suggest a relatively high degree of activity along the both sides of the Kemalpa?a Basin. Similarly, the valley floor width-to-height ratios (V_f) obtained from the both sides indicate low values varying from 0.043 to 0.92, which are typical values (<1) for tectonically active mountain fronts. The all values obtained are lower for the southern side. Therefore, we suggest that the tectonic activity of the Kemalpa?a Fault higher than the Spilda?? Fault Zone. This difference that can be arised from the different uplift rates also reveals the typical asymmetric characteristics of the Kemalpa?a Basin. Additionally, the trapezoidal facets which have been observed on the southern side of the basin indicate that the Kemalpa?a Fault is evolutionally more active as compared to the Spilda?? Fault Zone. The geomorphic indices indicate that the Quaternary landscape evolution of the Kemalpa?a Basin was governed by tectonic and erosional processes, and also the all results of morphometric analysis suggest a relatively high degree of tectonic activity along the faults bounding the Kemalpa?a Basin. Moreover, considering that active large normal faults with an average 15 km long can cause major earthquake, the earthquake hazard in the Kemalpa?a Basin should be investigated in detailed paleoseismological studies.     

Modeling of seawater intrusion in a coastal aquifer of Karaburun Peninsula,western Turkey

Seawater intrusion is a major problem to freshwater resources especially in coastal areas where fresh groundwater is surrounded and could be easily influenced by seawater. This study presents the development of a conceptual and numerical model for the coastal aquifer of Karareis region (Karaburun Peninsula) in the western part of Turkey. The study also presents the interpretation and the analysis of the time series data of groundwater levels recorded by data loggers. The SEAWAT model is used in this study to solve the density-dependent flow field and seawater intrusion in the coastal aquifer that is under excessive pumping particularly during summer months. The model was calibrated using the average values of a 1-year dataset and further verified by the average values of another year. Five potential scenarios were analyzed to understand the effects of pumping and climate change on groundwater levels and the extent of seawater intrusion in the next 10 years. The result of the analysis demonstrated high levels of electrical conductivity and chloride along the coastal part of the study area. As a result of the numerical model, seawater intrusion is simulated to move about 420 m toward the land in the next 10 years under “increased pumping” scenario, while a slight change in water level and TDS concentrations was observed in “climate change” scenario. Results also revealed that a reduction in the pumping rate from Karareis wells will be necessary to protect fresh groundwater from contamination by seawater.     

Intensity Oscillation in the Corona as Observed during the Total Solar Eclipse of 29 March 2006

We obtained the images of the eastern part of the solar corona in the Fe xiv 530.3 nm (green) and Fe x 637.4 nm (red) coronal emission lines during the total solar eclipse of 29 March 2006 at Manavgat, Antalya, Turkey. The images were obtained using a 35 cm Meade telescope equipped with a Peltier-cooled 2k × 2k CCD and 0.3 nm pass-band interference filters at the rates of 2.95 s (exposure times of 100 ms) and 2.0 s (exposure times of 300 ms) in the Fe xiv and Fe x emission lines, respectively. The analysis of the data indicates intensity variations at some locations with period of strongest power around 27 s for the green line and 20 s for the red line. These results confirm earlier findings of variations in the continuum intensity with periods in the range of 5 to 56 s by Singh et al. (Solar Phys. 170, 235, 1997). The wavelet analysis has been used to identify significant intensity oscillations at all pixels within our field of view. Significant oscillations with high probability estimates were detected for some locations only. These locations seem to follow the boundary of an active region and in the neighborhood, rather than within the loops themselves. These intensity oscillations may be caused by fast magneto-sonic waves in the solar corona and partly account for heating of the plasma in the corona.     

Effect of Newtonian Cooling on Waves in a Magnetized Isothermal Atmosphere

We examine the influence of nonadiabatic effects on the modes of an isothermal stratified magnetic atmosphere. The present investigation is a continuation of earlier work by Hasan and Christensen-Dalsgaard (1992) and Banerjee, Hasan, and Christensen-Dalsgaard (1995, 1996), where the interaction of various elementary modes in a stratified magnetized atmosphere was studied in the purely adiabatic limit. The inclusion of radiative dissipation based on Newton's law of cooling demonstrates the importance of this effect in the study of magnetoatmospheric waves. We analyze the physical nature of magnetoacoustic gravity (or MAG) oscillations in the presence of Newtonian cooling and find that the eigenfrequency curves in the diagnostic diagram, as in the previous analysis, undergo avoided crossings. However, the qualitative nature of the mode interaction is strongly influenced by radiative dissipation, which leads to strong mode damping in the avoided-crossing regions. We demonstrate this effect for the interaction between the Lamb mode and a magnetic mode. Our results could be important in the analysis of waves in flux tubes on the Sun.     

A survey of damage observed in Izmir due to 2020 Samos-Izmir earthquake

Natural Hazards - An earthquake of magnitude 6.9 hit the city of Izmir (Turkey) on 30 October 2020, resulting in 117 deaths (in Turkey) and considerable economic losses. The earthquake also...