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In this study, a groundwater exploration survey was conducted using the DC Resistivity (DCR) method in a hydrogeological setting containing a perched aquifer. DCR data were gathered and an electrical tomography section was recovered using conventional four-electrode instruments with a Schlumberger array and a two-dimensional (2D) inversion scheme. The proposed scheme was tested over a synthetic three-dimensional (3D) subsurface model before deploying it in a field situation. The proposed method indicated that gathering data with simple four-electrode instruments at stations along a line and 2D inversion of datasets at multiple stations can recover depth intervals of the studied aquifer in the hydrogeological setting even if it has a 3D structure. In this study, 2D inversion of parallel profiles formed a pseudo-3D volume of the subsurface resistivity structures and mapped out multiple resistive (>25 ohm·m) bodies at shallow (between 50–100 m) and deep sections (>150 m). In general, the proposed method is convenient to encounter geological units that have limited vertical and spatial extensions in any direction and presents resistivity contrast from groundwater-bearing geologic materials.

Tectonic structures in the Black Sea and the Levantine Sea were mapped using satellite gravity data. The relationship between Antalya and Cyprus arcs is revealed by the deformation traces of the arc formation. The Cyprus arc which over the slice that disappears from the South of the Anaximander seamounts to the Northeast, can traceable at the western end of the Antalya Bay. The distinction of western and eastern basins in the Black Sea is also mapped. Due to the low spatial resolution, additional studies with higher resolution are required. [ABSTRACT FROM AUTHOR]

ABSTRACT Marine magnetotelluric measurements using 'free-fall'' instruments without effective compasses suffer from the problem of unknown orientation of the receivers at the seafloor. While past works indicate that marine magnetotelluric orientation of the instruments can be estimated by reference to land deployments of known orientation using the transfer tensor method, there is limited published information on how this is implemented in practice. We document this method and propose a set of new time- and frequency-domain approaches to solve this orientation problem of the seafloor receivers. We test these methodologies in onshore and offshore magnetotelluric data whose orientations are well known and apply these techniques to marine magnetotelluric data with unknown orientation. For the controlled tests, both time- and frequency-domain approaches produce overall comparable results. To investigate the effects of the subsurface structure distribution on the orientation process, a dimensionality analysis of a controlled dataset is carried out. In subsequent analysis using the available disoriented marine magnetotelluric data from offshore Brazil and from the Vassouras magnetic observatory on the mainland for remote referencing, frequency-domain methods yield approximate orientation angles among themselves with low standard deviation each. Time-domain results are consistent for most cases but differ from frequency-domain results for some situations. [ABSTRACT FROM AUTHOR]

The relation between seismic P and S-wave velocities, standard penetration test blow counts (SPT-N) and relative density are the subject of our research. We focused especially on variations of SPT-N versus seismic velocities and relative density versus seismic velocities. Contrary to the traditional approach, the scattered nature of the graphs led us to define the empirical relations as upper and lower bounds instead of single average curves. The values, calculated from the upper and lower limits, have large ranges and, therefore, span whole observable values of the site and geological unit. The wideness of the range between the upper and lower limit recommends that if a geotechnical parameter is required for the assessment of the soil condition; direct gathering from the field or core sample must be employed for a realistic evaluation. [ABSTRACT FROM AUTHOR]