Comparison of geophysical methods for sub-surface mapping of faults and fracture zones in a section of the Viggja road tunnel, Norway

Ganerød, Guri V.; Rønning, Jan Steinar; Dalsegg, Einar; Elvebakk, Harald; Holmøy, Kristin Hilde; Nilsen, Bjørn; Braathen, Alvar

doi:10.1007/s10064-006-0041-6

Cited by 43 publications

(33 citation statements)

References 4 publications

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“…Therefore, those faults assisted in understanding the complicated hydrogeological conditions of this area. Ganerød et al (2006) reported that in most cases, 2D resistivity clearly identifies zones in the bedrock that can be observed as fault and/or fracture zones and the results showed a good correlation between the resistivity profiles and mapped structures on the surface. On map (9), there are two traces of faults, the first is solid and the second is dashed.…”

Section: Curve Types and Fault Zone Determinationmentioning

confidence: 85%

“…However, differences in the anomaly signals between the water-filled conduit and other water-bearing features such as water-filled fracture zones were undistinguishable and the electricalresistivity method is useful in conduit detection by providing potential drilling targets. Ganerød et al (2006) compared among 2D resistivity, refraction seismic, and VLF for subsurface mapping of faults and fracture zones and showed that 2D resistivity data are most valuable for interpreting geological structures in the subsurface. With 2D resistivity, the position of a zone is well-identified.…”

Section: Hydro-geophysical Characteristicsmentioning

confidence: 99%

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Resistivity method contribution in determining of fault zone and hydro-geophysical characteristics of carbonate aquifer, eastern desert, Egypt

2018

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Determination of fault zone and hydro-geophysical characteristics of the fractured aquifers are complicated, because their fractures are controlled by different factors. Therefore, 60 VESs were carried out as well as 17 productive wells for determining the locations of the fault zones and the characteristics of the carbonate aquifer at the eastern desert, Egypt. The general curve type of the recorded rock units was QKH. These curves were used in delineating the zones of faults according to the application of the new assumptions. The main aquifer was included at end of the K-curve type and front of the H-curve type. The subsurface layers classified into seven different geoelectric layers. The fractured shaly limestone and fractured limestone layers were the main aquifer and their resistivity changed from low to medium (11-93 Ω m). The hydro-geophysical properties of this aquifer such as the areas of very high, high, and intermediate fracture densities of high groundwater accumulations, salinity, shale content, porosity distribution, and recharging and flowing of groundwater were determined. The statistical analysis appeared that depending of aquifer resistivity on the water salinities (T.D.S.) and water resistivities add to the fracture density and shale content. The T.D.S. increasing were controlled by Na + , Cl − , Ca 2+ , Mg 2+ , and then (SO 4 ) 2− , respectively. The porosity was calculated and its average value was 19%. The hydrochemical analysis of groundwater appeared that its type was brackish and the arrangements of cation concentrations were Na + > Ca 2+ > Mg 2+ > K + and anion concentrations were Cl − > (SO 4 ) 2− > HCO 3 − > CO 3 − . The groundwater was characterized by sodium-bicarbonate and sodium-sulfate genetic water types and meteoric in origin. Hence, it can use the DC-resistivity method in delineating the fault zone and determining the hydro-geophysical characteristics of the fractured aquifer with taking into account the quality of measurements and interpretation.

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Section: Curve Types and Fault Zone Determinationmentioning

confidence: 85%

Section: Hydro-geophysical Characteristicsmentioning

confidence: 99%

Resistivity method contribution in determining of fault zone and hydro-geophysical characteristics of carbonate aquifer, eastern desert, Egypt

2018

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“…All these effects reduce the possibility to map fracture zones in the subsurface, and modelling has shown that artificial effects, such as a widening of the zone with increasing depth, disproportionate resistivity values in the fracture zone, and artificial anomalies outside the fracture zone may occur in the measured data (Reiser et al 2009). Similar studies have also been carried out for the Viggja and Storsand tunnels at E 39 in Sør-Trøndelag County, Norway (Ganerød et al 2006;Ødegaard 2006). …”

Section: Introductionmentioning

confidence: 62%

Resistivity mapping as a tool for identification and characterisation of weakness zones in crystalline bedrock: definition and testing of an interpretational model

Rønning

Ganerød

Dalsegg

et al. 2013

Bull Eng Geol Environ

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In recent years, the focus on feasibility studies for tunnels has increased in Norway. Traditionally, the refraction seismic method and the very low-frequency electromagnetic method (VLF-EM) have been used. The Geological Survey of Norway introduced the electrical resistivity traversing method (ERT) in feasibility studies for tunnel construction purposes. Resistivity modelling shows that the method has the potential to characterise fracture zones geometrically; i.e., the thickness, dip, and depth extent. Based on previous studies, a model for mineralogical characterisation is proposed. This model, and the possibility for geometrical characterisation, is critically tested with success on three tunnel projects. The results of the comparison study, with regards to weakness zones, show that VLF-EM is a method that is capable of locating fracture zones, while refraction seismic is capable of locating and indicating the width of the zone, and can be used to imply the thickness of the soil cover above bedrock. The 2D resistivity method is able to locate the weakness zone, indicate the width, depth extent, and the dip of the zone, and in addition, characterise the zone with respect to stability or water problems. The crystalline bedrock characterisation is divided into three groups: resistivity values above 3,000 X m indicating good rock quality, values between 3,000 and 500 X m indicating bedrock with mainly water problems, while values \500 X m indicate clay-bearing, unstable rock with fewer water problems. From our investigations, we conclude that the 2D resistivity method is a very good supplement to traditional methods for feasibility studies on tunnelling purposes in crystalline rock.

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“…Cardarelli et al, 2003;Cavinato et al, 2006;Dahlin et al, 1999;Danielsen, 2007;Ganerød et al, 2006) the question asked by the engineers and decision makers is always: "How reliable are the results?". This can be difficult to answer, so numerical modelling is a useful tool to learn more about how to interpret IP and geoelectrical data in a specific geological environment.…”

Section: Introductionmentioning

confidence: 99%

Numerical Modelling for Improvement of the Interpretation of Geoelectrical and Induced Polarization Measurements

Danielsen

Dahlin

2008

Near Surface 2008 - 14th EAGE European Meeting of Environmental and Engineering Geophysics

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Comparison of geophysical methods for sub-surface mapping of faults and fracture zones in a section of the Viggja road tunnel, Norway

Cited by 43 publications

References 4 publications

Resistivity method contribution in determining of fault zone and hydro-geophysical characteristics of carbonate aquifer, eastern desert, Egypt

Resistivity method contribution in determining of fault zone and hydro-geophysical characteristics of carbonate aquifer, eastern desert, Egypt

Resistivity mapping as a tool for identification and characterisation of weakness zones in crystalline bedrock: definition and testing of an interpretational model

Numerical Modelling for Improvement of the Interpretation of Geoelectrical and Induced Polarization Measurements

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