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  • 1
    Online Resource
    Online Resource
    ANGUS+ - Auswirkungen der Nutzung des geologischen Untergrundes als thermischer, elektrischer oder stofflicher Speicher im Kontext der Energiewende : Dimensionierung, Risikoanalysen und Auswirkungsprognosen als Grundlagen einer zukünftigen Raumplanung des Untergrundes$dSchlussbericht zum Verbundvorhaben : Berichtszeitraum: 01.07.2012-30.06.2017 (2020)
    Kiel : Christian-Albrechts-Universität zu Kiel, Institut für Geowissenschaften
    Details Availability
    Keywords: Forschungsbericht ; Unterirdische Lagerung
    Type of Medium: Online Resource
    Pages: 1 Online-Ressource (202 Seiten, 3,46 MB) , Diagramme, Illustrationen, Karten
    URL: https://doi.org/10.2314/KXP:1834636248
    DOI: 10.2314/KXP:1834636248
    Language: German
    Note: Förderkennzeichen BMBF 03EK3022 A , Verbundnummer 01125906 , Literaturangaben , Unterschiede zwischen dem gedruckten Dokument und der elektronischen Ressource können nicht ausgeschlossen werden
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  • 2
    Book
    Book
    Seismische Anisotropie der kristallinen Kruste im Feldexperiment (1994)
    Details Availability
    Keywords: Erdkruste ; Kristallin ; Anisotropie ; Seismik ; Habilitationsschrift ; Hochschulschrift ; Erdkruste ; Kristallin ; Anisotropie ; Seismik
    Type of Medium: Book
    Pages: II, 243 S , Ill., graph. Darst , 30 cm
    Language: German
    Note: Kiel, Univ., Habil.-Schr. : 1994
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  • 3
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    A novel seismic full waveform inversion approach for assessing the internal structure of a medieval sea dike (2023)
    Details
    Publication Date: 2024-05-22
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉Coastal protection in the form of dike constructions has a long history at the German North Frisian coast dating back to the High Middle Ages. As the vast majority of the dikes built prior to the devastating storm surges of the Middle Ages have been irretrievably destroyed, mostly sparse remains and only a few well preserved of these medieval dikes are found along the German North Frisian coast and within the Wadden Sea. Not all details of their construction and dimensions are yet understood. In the present case study, we investigate the historical Schardeich on the island of Pellworm in the German North Sea in a noninvasive way using shear waves (SH‐waves). For the data interpretation, we applied a combination of seismic full waveform inversion and classical seismic reflection imaging to determine the interior structure of the dike and its underlying layers at the highest possible resolution. The results obtained on land are compared with dike remains found in the tidal flats. These remains show up in marine seismic sections as characteristic reflections, which probably represent a compaction layer caused by the load of the former dike. For ground truthing, we compare the seismic results with internal dike structures found in nearby excavations. The comparison highlights that FWI is a reliable tool for near‐surface archaeological prospecting. We find that SH‐wave FWI provides decimetre‐scale velocity and density models that allow, together with the seismic reflection section, to determine distinct construction phases of the dike. The investigated dike further shows a depression at base level of about 0.75 m, which is of the same order as observed for the dike base reflections in the tidal flats. Transferring these findings to the dike remains mapped in the tidal flats, we derive a height of the former dike from 2.2 to 4.4 m.〈/p〉
    Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Keywords: ddc:622.1592 ; archaeogeophysics ; high‐resolution seismic reflection imaging ; seismic full waveform inversion ; shear‐wave seismic
    Language: English
    Type: doc-type:article
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    CITATION GEO-LEO
  • 4
    Electronic Resource
    Electronic Resource
    An automated ray method for diffraction modelling in complex media (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical journal international 116 (1994), S. 0 
    Details
    ISSN: 1365-246X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: We present the computational concept and first results of an automated 2-D ray-tracing algorithm which combines the standard ray method with the method of edge waves and paraxial ray tracing. Reliable ray synthetic seismograms are obtained for subsurface structures of high complexity. Both diffracted and multiple diffracted arrivals are automatically computed, complementing all types of primary arrivals (reflected, multiple reflected, converted waves, etc.) where geometric shadow zones are caused by edges (inhomogeneities) in the subsurface model. The method of computation can be summarized as follows: (1) during standard ray tracing, properties of central and paraxial rays are computed for a set of neighbouring rays. (2) Diffraction points (edges) are identified by comparing the amplitude and traveltime differences of neighbouring rays with the corresponding values of their paraxial approximation. (3) Detected edges are used as source points for diffracted rays. (4) Repetition of (1)-(3) for diffracted rays allows computation of multiple diffractions (‘diffracted diffractions’). (5) The amplitude decay of diffracted arrivals is computed according to the theory of edge waves. Its critical variables are expressed in terms of second-order paraxial traveltimes. The method is demonstrated for a simple and complex synthetic model and a real data complex model.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-246X.1994.tb02124.x
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    Paper (German National Licenses)
    Fulltext
  • 5
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    Ideas and perspectives: Land-ocean connectivity through groundwater (2022)
    Copernicus Publications (EGU)
    Details
    Publication Date: 2023-02-10
    Description: For millennia humans have gravitated towards coastlines for their resource potential and as geopolitical centres for global trade. A basic requirement ensuring water security for coastal communities relies on a delicate balance between the supply and demand of potable water. The interaction between freshwater and saltwater in coastal settings is, therefore, complicated by both natural and human-driven environmental changes at the land-sea interface. In particular, ongoing sea level rise, warming and deoxygenation might exacerbate such perturbations. In this context, an improved understanding of the nature and variability of groundwater fluxes across the land-sea continuum is timely, yet remains out of reach. The flow of terrestrial groundwater across the coastal transition zone as well as the extent of freshened groundwater below the present-day seafloor are receiving increased attention in marine and coastal sciences because they likely represent a significant, yet highly uncertain component of (bio)geochemical budgets, and because of the emerging interest in the potential use of offshore freshened groundwater as a resource. At the same time, “reverse” groundwater flux from offshore to onshore is of prevalent socio-economic interest as terrestrial groundwater resources are continuously pressured by overpumping and seawater intrusion in many coastal regions worldwide. An accurate assessment of the land-ocean connectivity through groundwater and its potential responses to future anthropogenic activities and climate change will require a multidisciplinary approach combining the expertise of geophysicists, hydrogeologists, (bio)geochemists and modellers. Such joint activities will lay the scientific basis for better understanding the role of groundwater in societal-relevant issues such as climate change, pollution and the environmental status of the coastal oceans within the framework of the United Nations Sustainable Development Goals. Here, we present our perspectives on future research directions to better understand land-ocean connectivity through groundwater, including the spatial distributions of the essential hydrogeological parameters, highlighting technical and scientific developments, and briefly discussing its societal relevance in rapidly changing coastal oceans.
    Type: Article , NonPeerReviewed , info:eu-repo/semantics/article
    Format: text
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    OceanRep: Article in a Scientific Journal - without review
  • 6
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    Formation and geophysical character of transitional crust at the passive continental margin around Walvis Ridge, Namibia (2022)
    Copernicus Publications (EGU)
    Details
    Publication Date: 2023-02-09
    Description: When interpreting geophysical models, we need to establish a link between the models’ physical parameters and geological units. To define these connections, it is crucial to consider and compare geophysical models with multiple, independent parameters. Particularly in complex geological scenarios, such as the rifted passive margin offshore Namibia, multi-parameter analysis and joint inversion are key techniques for comprehensive geological inferences. The models resulting from joint inversion enable the definition of specific parameter combinations, which can then be ascribed to geological units. Here we perform a user-unbiased clustering analysis of the parameters electrical resistivity and density from two models derived in a joint inversion along the Namibian passive margin. We link the resulting parameter combinations to break-up related lithology, and infer the history of margin formation. This analysis enables us to clearly differentiate two types of sediment cover. Namely, one of near-shore, thick, clastic sediments, and a second one of further offshore located, more biogenic, marine sediments. Furthermore, we clearly identify areas of interlayered massive, and weathered volcanic flows, which are usually only identified in reflection seismic studies as seaward dipping reflectors. Lastly, we find a distinct difference in the signature of the transitional crust south of- and along the supposed hot-spot track Walvis Ridge. We ascribe this contrast to an increase in magmatic activity above the volcanic centre along Walvis Ridge, and potentially a change in melt sources or depth of melting. This characterizes a rift-related southern complex, and a plume-driven Walvis Ridge regime. All of these observations demonstrate the importance of multi-parameter geophysical analysis for large-scale geological interpretations. Furthermore, our results may improve future joint inversions using direct parameter coupling, by providing a guideline for the complex passive margins parameter correlations.
    Type: Article , NonPeerReviewed
    Format: text
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    OceanRep: Article in a Scientific Journal - without review
  • 7
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    Comparison of Different Coupling Methods for Joint Inversion of Geophysical data: A case study for the Namibian Continental Margin (2021)
    AGU (American Geophysical Union) | Wiley
    Details
    Publication Date: 2024-02-07
    Description: Integration of multiple geophysical data is a key practice to reduce model uncertainties and enhance geological interpretations. Electrical resistivity models resulting from inversion of marine magnetotelluric (MT) data, often lack depth resolution of lithological boundaries and distinct information for shallow model parts. This is due to the diffusive nature of electromagnetic fields, enhanced by deficient data sampling and model regularization during inversion. Thus, integrating data or models to constrain layer thicknesses or structural boundaries is an effective approach to derive better constrained and more detailed resistivity models. We investigate the different impacts of three cross-gradient coupled constraints on 3D MT inversion of data from the Namibian passive continental margin. The three constraints are a) coupling with a fixed structural density model; b) coupling with satellite gravity data; c) coupling with a fixed gradient velocity model. Here we show that coupling with a fixed model (a and c) improves the resistivity model the most. Shallow conductors imaging sediment cover are confined to a thinner layer in the resulting resistivity models compared to the MT-only model. Additionally, these constraints help to suppress vertical smearing of a conductive anomaly attributed to a fracture zone, and clearly show that the seismically imaged Moho is not accompanied by a change in electrical resistivity. All of these observations help to derive an Earth model, which will form the basis for future interpretation of the processes that lead to continental break-up during the early Cretaceous.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: other
    Format: text
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  • 8
    facet.materialart.
    Unknown
    Formation and geophysical character of transitional crust at the passive continental margin around Walvis Ridge, Namibia (2023)
    Copernicus Publications (EGU)
    Details
    Publication Date: 2024-02-07
    Description: When interpreting geophysical models, we need to establish a link between the models’ physical parameters and geological units. To define these connections, it is crucial to consider and compare geophysical models with multiple, independent parameters. Particularly in complex geological scenarios, such as the rifted passive margin offshore Namibia, multi-parameter analysis and joint inversion are key techniques for comprehensive geological inferences. The models resulting from joint inversion enable the definition of specific parameter combinations, which can then be ascribed to geological units. Here we perform a user-unbiased clustering analysis of the parameters electrical resistivity and density from two models derived in a joint inversion along the Namibian passive margin. We link the resulting parameter combinations to break-up related lithology, and infer the history of margin formation. This analysis enables us to clearly differentiate two types of sediment cover. Namely, one of near-shore, thick, clastic sediments, and a second one of further offshore located, more biogenic, marine sediments. Furthermore, we clearly identify areas of interlayered massive, and weathered volcanic flows, which are usually only identified in reflection seismic studies as seaward dipping reflectors. Lastly, we find a distinct difference in the signature of the transitional crust south of- and along the supposed hot-spot track Walvis Ridge. We ascribe this contrast to an increase in magmatic activity above the volcanic centre along Walvis Ridge, and potentially a change in melt sources or depth of melting. This characterizes a rift-related southern complex, and a plume-driven Walvis Ridge regime. All of these observations demonstrate the importance of multi-parameter geophysical analysis for large-scale geological interpretations. Furthermore, our results may improve future joint inversions using direct parameter coupling, by providing a guideline for the complex passive margins parameter correlations.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
    Format: text
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 9
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    The Deserted Manor of Noer, Schleswig-Holstein, Germany. Geophysical Prospection Methods in Comparison (2022)
    EEGS (Environmental and Engineering Geophysical Society)
    Details
    Publication Date: 2024-02-07
    Description: Manors are an important component of the cultural-economic history of Northern Germany and Southern Scandinavia. We present the results of a geophysical prospection that led to the identification of a previously unknown manor near the village of Noer, Schleswig-Holstein, Northern Germany. Although magnetic gradiometry provides a fast way to cover large areas, it does not provide accurate depth estimates, is affected by magnetic blanking and is unable to detect differences in water content. Therefore, we applied a combination of different geophysical methods to optimize the non-invasive reconstruction of the target and its surroundings not only with respect to building structures but also in relation to the surrounding landscape. In particular, a combination of magnetics, ground-penetrating radar (GPR), electromagnetic induction (EMI), electrical resistivity tomography (ERT), and soil samples were carried out to determine: (1) the object's exact location; (2) the building structure and state of preservation; and (3) any additional structures in the surrounding area. We detected a tripartite building of 22 by 27 m, with several inner walls, which was located underneath a topographic high on the surveyed field. The bulk structure is identifiable most clearly in the magnetic and EMI inphase component maps. GPR profiles and soil samples indicate flooring or foundations in part of the building. Their shallow depths of less than 2 m below the surface and debris clusters close to the surface indicate at least partial demolition. A surrounding wall was found about 5 m outside the building. The area in between shows no magnetic anomalies, lower resistivities in EMI and ERT, and low GPR reflection amplitudes. Soil samples suggest a moat or other water feature. Archaeological artifacts found at the location characterize the building as a 16th to 17th century brick manor. Other objects, like a suspected farmyard and access path could not be found. A comparison with historical sources suggest that the mansion is in relation to the manor Grönwohld. After a change of the owner it was degraded to a Meierhof, and subsequently the building decayed and was forgotten.
    Type: Article , PeerReviewed
    Format: text
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 10
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    Unknown
    Ideas and perspectives: Land-ocean connectivity through groundwater (2023)
    Copernicus Publications (EGU)
    Details
    Publication Date: 2024-02-07
    Description: For millennia, humans have gravitated towards coastlines for their resource potential and as geopolitical centres for global trade. A basic requirement ensuring water security for coastal communities relies on a delicate balance between the supply and demand of potable water. The interaction between freshwater and saltwater in coastal settings is, therefore, complicated by both natural and human-driven environmental changes at the land-sea interface. In particular, ongoing sea level rise, warming and deoxygenation might exacerbate such perturbations. In this context, an improved understanding of the nature and variability of groundwater fluxes across the land-sea continuum is timely, yet remains out of reach. The flow of terrestrial groundwater across the coastal transition zone as well as the extent of freshened groundwater below the present-day seafloor are receiving increased attention in marine and coastal sciences because they likely represent a significant, yet highly uncertain component of (bio)geochemical budgets, and because of the emerging interest in the potential use of offshore freshened groundwater as a resource. At the same time, “reverse” groundwater flux from offshore to onshore is of prevalent socio-economic interest as terrestrial groundwater resources are continuously pressured by overpumping and seawater intrusion in many coastal regions worldwide. An accurate assessment of the land-ocean connectivity through groundwater and its potential responses to future anthropogenic activities and climate change will require a multidisciplinary approach combining the expertise of geophysicists, hydrogeologists, (bio)geochemists and modellers. Such joint activities will lay the scientific basis for better understanding the role of groundwater in societal-relevant issues such as climate change, pollution and the environmental status of the coastal oceans within the framework of the United Nations Sustainable Development Goals. Here, we present our perspectives on future research directions to better understand land-ocean connectivity through groundwater, including the spatial distributions of the essential hydrogeological parameters, highlighting technical and scientific developments, and briefly discussing its societal relevance in rapidly changing coastal oceans.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
    Location Call Number Limitation Availability
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    OceanRep: Article in a Scientific Journal - peer-reviewed
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