Combining ground-based and airborne EM through Artificial Neural Networks for modelling glacial till under saline  groundwater conditions

Gunnink, Jan; Bosch, J.H.A.; Siemon, B.; Roth, B.; Auken, Esben

doi:10.5194/hess-16-3061-2012

Cited by 48 publications

(45 citation statements)

References 32 publications

(23 reference statements)

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“…Studies with related combinations of methods are shown, e.g. by Jørgensen et al (2012), Bosch et al (2009), Rumpel et al (2009), Sulzbacher et al (2012) and Gunnink et al (2012).…”

Section: T Burschil Et Al: Compiling Geophysical and Geological Infmentioning

confidence: 99%

Compiling geophysical and geological information into a 3-D model of the glacially-affected island of Föhr

Burschil

Scheer

Kirsch

et al. 2012

Hydrol. Earth Syst. Sci.

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Abstract. Within the scope of climatic change and associated sea level rise, coastal aquifers are endangered and are becoming more a focus of research to ensure the future water supply in coastal areas. For groundwater modelling a good understanding of the geological/hydrogeological situation and the aquifer behavior is necessary. In preparation of groundwater modelling and assessment of climate change impacts on coastal water resources, we setup a geological/hydrogeological model for the North Sea Island of Föhr.Data from different geophysical methods applied from the air, the surface and in boreholes contribute to the 3-D model, e.g. airborne electromagnetics (SkyTEM) for spatial mapping the resistivity of the entire island, seismic reflections for detailed cross-sections in the groundwater catchment area, and geophysical borehole logging for calibration of these measurements. An iterative and integrated evaluation of the results from the different geophysical methods contributes to reliable data as input for the 3-D model covering the whole island and not just the well fields.The complex subsurface structure of the island is revealed. The local waterworks use a freshwater body embedded in saline groundwater. Several glaciations reordered the youngest Tertiary and Quaternary sediments by glaciotectonic thrust faulting, as well as incision and refill of glacial valleys. Both subsurface structures have a strong impact on the distribution of freshwater-bearing aquifers. A digital geological 3-D model reproduces the hydrogeological structure of the island as a base for a groundwater model. In the course of the data interpretation, we deliver a basis for rock identification.We demonstrate that geophysical investigation provide petrophysical parameters and improve the understanding of the subsurface and the groundwater system. The main benefit of our work is that the successful combination of electromagnetic, seismic and borehole data reveals the complex geology of a glacially-affected island. A sound understanding of the subsurface structure and the compilation of a 3-D model is imperative and the basis for a groundwater flow model to predict climate change effects on future water resources.

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“…Studies with related combinations of methods are shown, e.g. by Jørgensen et al (2012), Bosch et al (2009), Rumpel et al (2009), Sulzbacher et al (2012) and Gunnink et al (2012).…”

Section: T Burschil Et Al: Compiling Geophysical and Geological Infmentioning

confidence: 99%

Compiling geophysical and geological information into a 3-D model of the glacially-affected island of Föhr

Burschil

Scheer

Kirsch

et al. 2012

Hydrol. Earth Syst. Sci.

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“…Other automatic methods of integrating AEM data into geological models are geostatistical methods presented by, for example, Gunnink et al (2012), using artificial neural networks, or He et al (2014), using transition probabilities.…”

Section: Advantages and Limitationsmentioning

confidence: 99%

Performance evaluation of groundwater model hydrostratigraphy from airborne electromagnetic data and lithological borehole logs

Marker

Foged

et al. 2015

Hydrol. Earth Syst. Sci.

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Abstract. Large-scale hydrological models are important decision support tools in water resources management. The largest source of uncertainty in such models is the hydrostratigraphic model. Geometry and configuration of hydrogeological units are often poorly determined from hydrogeological data alone. Due to sparse sampling in space, lithological borehole logs may overlook structures that are important for groundwater flow at larger scales. Good spatial coverage along with high spatial resolution makes airborne electromagnetic (AEM) data valuable for the structural input to large-scale groundwater models. We present a novel method to automatically integrate large AEM data sets and lithological information into large-scale hydrological models. Clayfraction maps are produced by translating geophysical resistivity into clay-fraction values using lithological borehole information. Voxel models of electrical resistivity and clay fraction are classified into hydrostratigraphic zones using kmeans clustering. Hydraulic conductivity values of the zones are estimated by hydrological calibration using hydraulic head and stream discharge observations. The method is applied to a Danish case study. Benchmarking hydrological performance by comparison of performance statistics from comparable hydrological models, the cluster model performed competitively. Calibrations of 11 hydrostratigraphic cluster models with 1-11 hydraulic conductivity zones showed improved hydrological performance with an increasing number of clusters. Beyond the 5-cluster model hydrological performance did not improve. Due to reproducibility and possibility of method standardization and automation, we believe that hydrostratigraphic model generation with the proposed method has important prospects for groundwater models used in water resources management.

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“…However, it is common to measure the attitude variations of ATEM systems directly or indirectly by installing an inertial navigation system or two laser altimeters, differential Global Position System (GPS) devices and inclinometers (Gunnink et al, 2012;Hefford et al, 2006;Smith, 2001), and then we can use the Neumann mutual inductance formula and the measured attitude variations to transform the coordinates of circular coils or polygonal coils at arbitrary attitudes with a rotation matrix. Thus the singular values of two vertical coils can be calculated as well as the mutual inductance of polygonal and circular coils at arbitrary attitudes and arbitrary positions.…”

Section: Introductionmentioning

confidence: 99%

The mutual inductance calculation between circular and quadrilateral coils at arbitrary attitudes using a rotation matrix for airborne transient electromagnetic systems

Wang

Lin

et al. 2014

Journal of Applied Geophysics

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Combining ground-based and airborne EM through Artificial Neural Networks for modelling glacial till under saline groundwater conditions

Cited by 48 publications

References 32 publications

Compiling geophysical and geological information into a 3-D model of the glacially-affected island of Föhr

Compiling geophysical and geological information into a 3-D model of the glacially-affected island of Föhr

Performance evaluation of groundwater model hydrostratigraphy from airborne electromagnetic data and lithological borehole logs

The mutual inductance calculation between circular and quadrilateral coils at arbitrary attitudes using a rotation matrix for airborne transient electromagnetic systems

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