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1

An improved grey wolf optimizer algorithm for the inversion of geoelectrical data

Li S.-Y., Wang S.-M., Wang P.-F., Su X.-L., Zhang X.-S., Dong Z.-H.

Acta Geophysica

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2018

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Vol. 66, no. 4

607--621

EN

The grey wolf optimizer (GWO) is a novel bionics algorithm inspired by the social rank and prey-seeking behaviors of grey wolves. The GWO algorithm is easy to implement because of its basic concept, simple formula, and small number of parameters. This paper develops a GWO algorithm with a nonlinear convergence factor and an adaptive location updating strategy and applies this improved grey wolf optimizer (improved grey wolf optimizer, IGWO) algorithm to geophysical inversion problems using magnetotelluric (MT), DC resistivity and induced polarization (IP) methods. Numerical tests in MATLAB 2010b for the forward modeling data and the observed data show that the IGWO algorithm can find the global minimum and rarely sinks to the local minima. For further study, inverted results using the IGWO are contrasted with particle swarm optimization (PSO) and the simulated annealing (SA) algorithm. The outcomes of the comparison reveal that the IGWO and PSO similarly perform better in counterpoising exploration and exploitation with a given number of iterations than the SA.

2

Mapping of the north-eastern part of Kozłowicka buried valley based on geoelectrical data

Topolewska S., Stępień M., Kowalczyk S.

Studia Quaternaria

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2016

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Vol. 33, Nr 2

91--101

EN

The paper is aiming to determinate the extent of the northeastern arm of Kozłowicka buried valley on the grounds of own research by means of electrical resistivity tomography – ERT and available archival researches. On the Hydrogeological map of Poland, Żyrardów sheet (Felter and Nowicki, 1998a, b) Kozłowicka buried valley was differentiated as an individual hydrogeological unit. The results of the analysis show that the extent of the structure, defined by its upper boundary, differs significantly from the one suggested on the sheet of Hydrogeological map of Poland. Since there was no data available in the northeastern part of the discussed arm of Kozłowicka buried valley, the northern boundary was defined only based on available geoelectrical sounding profiles (Czerwińska, 1988; Topolewska, 2015). In order to confirm suggested solution, geoelectrical research by means of electrical resistivity tomography (ERT) was conducted. The measurements were performed along 3 profiles located in the area of interest. The authors would like to point out the need of the usage of ERT in mapping and studying buried structures that might be groundwater reservoirs. As a result, one obtains quasi-continuous image of electrical resistivity of the subsurface. Due to the contrast of electrical properties of sediments, it is possible to determine upper and bottom surfaces of electrical properties sediments, it is possible to determine upper and bottom surfaces of buried structures, formed within glacial deposits.

3

Obrazowanie elektrooporowe warunków hydrogeologicznych strefy brzegowej wyspy Wolin

Pacanowski G.

Biuletyn Państwowego Instytutu Geologicznego

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2016

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nr 466

225--232

PL

W artykule zaprezentowano problematykę złożonych warunków hydrogeologicznych w strefie brzegowej wyspy Wolin, które można obrazować za pomocą metod geoelektrycznych. Wody podziemne warstw wodonośnych strefy brzegowej znajdują się w stałym kontakcie z zasolonymi wodami morskimi. Fakt ten stanowi groźbę degradacji wód podziemnych i decyduje o specyfice ich ochrony. W utworach czwartorzędowych, na obszarach, gdzie wody podziemne wykazują niską mineralizację, wartości oporności utworów przepuszczalnych i nieprzepuszczalnych różnią się zdecydowanie, w związku z tym klasyfikacja hydrogeologiczna wyników, jakie otrzymujemy z pomiarów elektrooporowych nie stanowi problemu. Na obszarze prowadzonych badań sytuacja jest zupełnie inna i dużo bardziej skomplikowana, ze względu na ingresję słonych wód morskich do warstw wodonośnych. Co więcej, pośrednio mineralizacja ma również wpływ na oporności utworów słabo przepuszczalnych i praktycznie nieprzepuszczalnych.

EN

The article discusses the problem of complex hydrogeological conditions in the coastal zone of Wolin Island in Poland. Hydrogeological situation of the island was imaged by geoelectrical methods. Groundwater of the coastal zone is in constant contact with the saline sea waters. This fact constitutes a threat of groundwater degradation and has an influence on the methods of groundwater protection. The resistivity of Quaternary permeable and impermeable deposits is significantly different in areas where groundwater is characterized by low values of total dissolved solids (TDS). This implies that hydrogeological classification of the results obtained from electrical resistivity tomography (ERT) is not difficult. In the study area, the situation is completely opposite and much more complicated because of salty sea water ingress into aquifers. This affects the resistivity values of permeable and impermeable deposits, obtained from geophysical tests.

4

Comparing parallel programming environments for the joint inversion of geoelectrical data

Pięta A., Bała J.

Computer Science

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2009

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Vol. 10

85-95

EN

The article presents the comparison of the implementation of the inverse problem in geoelectrical methods in two different parallel computational environments. Combination of Monte Carlo method and Multistart algorithm was applied in the inversion process. Parallelization was done by fine grain decomposition. Execution time, speed-up and efficiency received for parallel algorithms in both computational environments were presented and analyzed.

PL

W artykule przedstawiono porównanie równoległej implementacji zagadnienia odwrotnego dla metod geoelektrycznych w dwóch różnych środowiskach obliczeniowych. Do rozwiązania zadania odwrotnego użyto algorytmu Monte Carlo – Multistart. W przypadku równoległej realizacji zastosowano drobnoziarnistą dekompozycję inwersji danych geoelektrycznych. Analizowano czas, przyśpieszenie i efektywność algorytmu równoległego w dwóch różnych środowiskach obliczeniowych.