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DC resistivity inversion constrained by magnetic method through sequential inversion

Varfnezhad Ramin, Parnow Saeed, Florio Giovanni, Fedi Maurizio, Vizheh Mehdi Mohammadi

Acta Geophysica

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2023

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Vol. 71, no. 1

247--260

EN

In the inversion of geophysical data, an attempt is made to obtain a model with the best ft on the observed data. Unfortunately, the results are usually accompanied by non-uniqueness and ambiguity. These inversion problems can be reduced by inverting different geophysical datasets. Sequential inversion is one of the most common ways to integrate two or more geophysical datasets, to obtain a model that is compatible with all geophysical data, thus reducing the amount of ambiguity. This paper presents separate inversions of DC resistivity and magnetic data and sequential inversion of DC resistivity constrained by magnetic data. Here, the inverse model of magnetic data is considered the initial model for the sequential inversion of DC resistivity data. At first, the algorithm is applied to a synthetic model composed of four conductive and magnetized bodies, and the results show notable improvement for the resistivity model after sequential inversion, compared with the separate resistivity inversion model. Finally, encouraged by the results obtained in the synthetic case, the algorithm was applied to DC resistivity and magnetic datasets that were collected in the archeological area of old Pompeii city nearby Naples, Italy. The result of the sequential resistivity inversion model was notably superior to the corresponding resistivity model obtained from standard separate inversion.

2

Application of the conductive method in the engineering geology: Ruczaj district in Kraków, Poland, as a case study

Klityński Wojciech, Oryński Szymon, Dinh Chau Nguyen

Acta Geophysica

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2019

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Vol. 67, no. 6

1791--1798

EN

The Ruczaj district in Kraków is the potential building area of high flat blocks for inhabitants. This area is built of the gypsum basement covered by the soil and impermeable clay beds with several meters of thickness. The flat blocks must be set on the textured gypsum layer. In the result of the rainfall and static pressure of the blocks, the water with SO42− increases up to the groundwater level, become the great threat for the flat blocks. The water creates specific hydrogeological conditions occurring in the zone of the building’s foundations. To eliminate the mentioned threat, we should determine precisely the thickness of the soil and impermeable clay as well as the depth of the gypsum basement. Based on the electromagnetic parameters of the geological formations, the Ground Conductivity Meter and DC resistivity methods were used to solve the mentioned problems.

3

Frequency and temperature dependence of dielectric and electric properties of Ba2-xSm4+2x/3Ti8O24 with structural analysis

Narang S. B., Kaur D., Pubby K.

Materials Science Poland

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2015

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Vol. 33, No. 2

268--277

EN

Dielectric ceramics samples of barium titanium oxide doped with samarium, having a complex structural formula of Ba2-xSm4+2x/3Ti8O24 (referred to as BST), were fabricated by a high temperature solid-state reaction technique with varying x (0.0, 0.2, 0.4, 0.6). X-ray diffraction technique was used to check the formation of particular phases. Scanning electron microscope technique was used to study the surface morphology of the samples. The samples were studied in a temperature range of 298 K to 623 K and frequency range of 10 KHz to 1 MHz. The dielectric constant (εr), loss tangent (tanδ), and AC conductivity (σAC) were measured on sintered disks of BST samples. The DC resistivity of different compositions was measured at room temperature. Detailed studies of dielectric and electrical properties showed that these properties are strongly dependent on composition, frequency and temperature. The compounds showed stable behavior in lower temperature range (up to 523 K), therefore, they can be used in practical applications in this temperature range.

4

DC resistivity studies of shallow geology in the vicinity of Vistula River flood bank in Czernichów village (near Kraków in Poland)

Mościcki W. J., Bania G., Ćwiklik M., Borecka A.

Studia Geotechnica et Mechanica

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2014

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Vol. 36, nr 1

63--70

EN

DC resistivity methods, soundings and Electrical Resistivity Tomography, were applied to study shallow geology in the place of planned construction of an experimental flood bank. The geoelectrical surveys provided quantitative information about the spatial presence of the various geoelectrical/geological layers: alluvial soils, sands, gravels and clays. ERT allowed maps to be constructed showing subsurface structure. A combination of geoelectrical and geological information resulted in a much better identification of the geological structure.