Wyniki wyszukiwania - BazTech

1

Karstic landscape detection using electrical resistivity tomography in northeast Algerian

Brahmi Serhane, Hadji Riheb, Chemseddine Fehdi, Brahmi Smail, Hamad Amor, Hamed Younes

Geomatics, Landmanagement and Landscape

|

2022

|

no. 3

103--115

EN

Sinkhole (doline) collapse is one of the major natural hazards threatening people and property in the Middle East and North Africa (MENA) region, especially if the bedrock structure is epi-karstic, covered by encrusted material. Many dolines-avens collapses have been recorded in urban and rural areas in Northeast Algeria. Our study identifies localized deformation that may be caused by a sinkhole activity based on the electrical resistivity tomography (ERT) imaging in Setifian high plains. For this task, we conducted 2-D Wenner and Wenner-Schlumberger transects profiles. The geological and hydrogeological study helped to calibrate the resistivity model, and in this regard, expound on the proneness of the limestone layer to collapse. The obtained model highlights the heterogeneity of the subsurface. The inverted transects allowed the investigation of 20 m depth with Wenner array and 52 m with Wenner-Schlumberger. The Wenner inverted models imaged the chimney and different karst networks until 20 m depth; even as the Wenner-Schlumberger models imaged a new karstic cavity in the limestone layer. ERT imaging has once again proven its effectiveness in mapping sinkholes based on its ability to detect resistivity. Our research can certainly benefit karst collapse monitoring in other areas of the high plain region.

2

Zastosowanie badań geofizycznych do rozpoznawania warunków geologicznych otoczenia złoża hydrogeotermalnego w masywie krystalicznym w rejonie Lądka-Zdroju

Stefaniuk M., Ostrowski C., Sada M., Cygal A.

Technika Poszukiwań Geologicznych

|

2017

|

R. 56, nr 2

131--146

PL

Rejon Lądka Zdroju jest od kilkuset lat znany z występowania i wykorzystywania ciepłych źródeł. Złoże wód geotermalnych występuje tutaj w specyficznych warunkach geologicznych charakterystycznych dla obszaru sudeckiego. Ma ono charakter szczelinowy i występuje w warunkach naporowych. Rozwój Uzdrowiska spowodował potrzebę lepszego rozpoznania złoża hydrogeotermalnego i jego geologicznego otoczenia. W ramach zrealizowanego programu badań wykonane zostały również badania geofizyczne zorientowane na rozpoznanie ogólnych warunków geologicznych złoża i jego otoczenia. Zastosowane zostały metody: magnetyczna, grawimetryczna i geotermiczna, profilowania VLF, sondowania i profilowania elektrooporowe oraz ciągłe profilowania magnetotelluryczne. W ramach prezentowanej pracy wykonany został przegląd wcześniejszych badań geofizycznych oraz wykonano reinterpretację danych magnetotellurycznych z włączeniem interpretacji danych grawimetrycznych. Reinterpretacja obejmowała przegląd prac pomiarowych, weryfikację procedur i wyników przetwarzania danych pomiarowych oraz została zweryfikowana i rozszerzona interpretacja krzywych sondowań w tym inwersyjne modelowania dwuwymiarowe. Badania te pozwoliły na wyinterpretowanie stref uskokowych, wykrycie anomalii temperaturowych i w bardzo ograniczonym stopniu rozpoznanie przestrzenne szczelinowych poziomów wodonośnych.

EN

The Lądek-Zdrój area has been known for several hundred years as a place of occurrence and use of hot springs. A hydrogeothermal reservoir occur there in specific geological conditions characteristic for Sudetes area. The reservoir is of a fracture type and occurs in artesian conditions. The development of the Health Resort caused the need for the better recognition of the hydrogeothermal reservoir and its geological vicinity. The carried out investigation program included, among others, a geophysical survey for the recognition of general geological conditions of the reservoir and its vicinity. The magnetic, gravity and surface geothermic methods were applied as well as VLF profiling, resistivity profiling and soundings and continuous magnetotelluric profiling. The review of the earlier geophysical surveys and reinterpretation of the magnetotelluric data including gravity data were made within the framework of the presented paper. The reinterpretation works a included review of data acquisition, the verification of procedures and results of data processing as well as verification and an extended interpretation of the sounding curves with use of inverse 2D modeling. As results of the survey tectonic zones were interpreted and temperature anomalies were discovered and, within a limited range, space recognition of the fractured aquifer horizons was made.

3

Field mapping of buried faults : a new approach applied in the Western Carpathians

Marko F., Dyda M., Gajdoš V., Rozimant K., Mojzeš A.

Geological Quarterly

|

2015

|

Vol. 59, No. 1

35--46

EN

Fault array in an area covered by Quaternary sediments and deprived of bedrock outcrops was investigated using fault trace mapping by geophysical methods and human feedback information from dowsing. The tectonics in the study area is dominated by a ENE-WSW fault zone affecting regional-scale structures. The fault network was approximated by dowsing-enhanced mapping and subsequently confirmed by field geophysical measurements using electromagnetic and radon emanometry methods. A resultant detailed map of structural discontinuities highlighted that combined dowsing and geophysical survey is an effective and reliable tool to identify buried faults. This approach with its low costs and fast field recognition is highly recommended for construction-work planning and for mineral resources exploration and exploitation.

4

Geophysical approach for assessment of seawater intrusion in the coastal aquifer of Wadi Nador (Tipaza, Algeria)

Bouderbala A., Remini B.

Acta Geophysica

|

2014

|

Vol. 62, no. 6

1352--1372

EN

The aquifer of Nador has suffered significant salinization due to seawater intrusion. It was strongly exploited during the 1980s and 1990s. A piezometric analysis in April 2012 showed the piezometric level to lie at 0 m a.s.l. over the plain; as a result, this aquifer is highly sensitive to the marine intrusion with an electrical conductivity of the groundwater in of exceeds 2500 μS/cm and so there are no abstractions for irrigation or drinking purpose from these sectors. The geoelectric study also showed the lateral variation in the electrical resistivity for two moments separated in time by more than 45 years. The fall in resistivity may be due to the encroachment of seawater into previously freshwater zones and/or infiltration during the era of pumped abstractions downstream. The resistivity surveys reveal two distinct sectors: the saturated aquifer in brackish and saltwater having resistivity values to 36-10 Ωm, which extends nearly 1600 m inland.

5

Zagrożenia pogórnicze na terenach dawnych podziemnych kopalń węgla brunatnego w rejonie Piły-Młyna (województwo Kujawsko-Pomorskie)

Kotyrba A., Frolik A., Kortas Ł., Siwek S.

Przegląd Górniczy

|

2012

|

T. 68, nr 7

58--66

PL

W artykule przedstawiono analizę warunków geologiczno-górniczych na terenach dawnych podziemnych kopalń węgla brunatnego w miejscowości Piła-Młyn w Gminie Gostycyn (województwo Kujawsko-Pomorskie, powiat Tucholski). Pod koniec XIX i w I połowie XX wieku w dolinie rzeki Brdy intensywną eksploatację złoża węgla brunatnego prowadziło kilka kopalń. Obecnie na części terenów pokopalnianych zlokalizowano osiedle domów jednorodzinnych. Powstanie w roku 2006 zapadliska powierzchni zaniepokoiło mieszkańców. W konsekwencji tego zdarzenia w latach 2008÷2009 na terenie osiedla przeprowadzono badania geofizyczne i geologiczne opisane w artykule.

EN

The article presents an analysis of geological and mining conditions in areas of former underground brown coal mines in Piła-Młyn (Kuyavian-Pomeranian Voivodeship, Tuchola administrative district). At the end of the 19 th and in the first half of the 20 th century several mines have conducted intense brown coal deposit extraction in the valley of the Brda river. Nowadays in a part of post-mining areas a housing estate of single family houses was located. The arisen in 2006 surface depression has alarmed the inhabitants. As a consequence of this event between 2008 and 2009 in the area of the housing estate geophysical and geological surveys described in the article were performed.

6

Inwersyjne obrazowanie oporu w rejonie złoża Zn-Pb Zawiercie Źródłem informacji na temat budowy geologicznej

Cabała J., Jochymczyk K., Poręba A.

Przegląd Geologiczny

|

2007

|

Vol. 55, nr 10

380-386

EN

The depletion of Zn-Pb ores in developed mining areas and the increase in metal prices have resulted in the need to search for new deposits which have not been exploited yet. A project of drilling new exploratory boreholes should be preceded by an interpretation of archival geological data. To obtain the most valuable information on the geological structure leading to its plausible interpretation, it seems to be purposeful and advisable to apply some geophysical methods that are reasonably cheap in comparison with others. The method of electrical resistivity tomography, which in this research uses two of many measurement protocols such as Schlumberger array and dipole-dipole array, is particularly useful. Computer interpretation of geophysical results allows a high resolution 2D and 3D geoelectrical model of rock mass to be created. The study was carried out using the multi-electrode Lund Imaging System manufactured by ABEM, Sweden. In order to evaluate the practical application of this method, Zawiercie Zn-Pb ore deposits were chosen as the area used in previous scientific research. Taking into account mineralization in its economic aspect, the deposits occur at relatively shallow depths of 50-120 m. In the investigated region, the Triassic carbonate formation overlays the Devonian rocks. The Keuper low-resistance clay, occurring on the surface, provides a very good electrical contact between an electrode and the soil. This is why there are favourable measurement conditions in this area. The boundaries between the Keuper, Devonian and Triassic formations are clearly noticeable in the resistivity cross-sections obtained. On the basis of the ERT results, it is possible to locate faulting zones as well as karst systems. One of the profiles clearly shows the occurrence of a low-resistance anomaly correlated with Zn-Pb mineralization, which was confirmed by borehole surveys. However, this early stage of the research with the use of the ERT method cannot unequivocally identify the ore body, particularly as it was conditioned by the limited depth of prospecting.

7

Rozpoznanie geofizyczne dla potrzeb budowy tunelu komunikacyjnego w utworach fliszu karpackiego

Pilecki Z.

Przegląd Górniczy

|

2001

|

T. 57, nr 10

11-14

PL

W artykule przedstawiono zastosowanie metod geofizycznych w budownictwie tunelowym. Zastosowanie to obejmuje fazy projektowania, budowy i eksploatacji tuneli. Podstawowe zadania badań geofizycznych dotyczą rozpoznania budowy geologicznej i właściwości mechanicznych górotworu na etapie projektowania tunelu oraz oceny zagrożeń dla stateczności obudowy tunelu na etapie jego budowy i eksploatacji. W artykule przedstawiono możliwości wybranych metod geofizycznych do realizacji konkretnych zadań badawczych.

EN

Application of geophysical methods in tunneling is presented in the paper. These methods are applied in the planning, construction and post-construction phases. The basic tasks of them apply to recognition of the rock mass geological structure and its mechanical properties in the designing stage and assessment of the hazards for the tunnel lining in the construction and explitation stages. The possibilities of geophysical methods application for specific research tasks are presented.