Sökning: "Thomas Kalscheuer"

Visar resultat 1 - 5 av 8 avhandlingar innehållade orden Thomas Kalscheuer.

  1. 1. Improvement and Assessment of Two-Dimensional Resistivity Models Derived from Radiomagnetotelluric and Direct-Current Resistivity Data

    Författare :Thomas Kalscheuer; Laust B. Pedersen; Christopher Juhlin; Roland Roberts; Heinrich Brasse; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Electromagnetic geophysics; radiomagnetotellurics; direct-current resistivity; displacement currents; dielectric effect; non-linearity; inversion; regularization; two-dimensional model; model variance; model resolution; data resolution; Geophysics; Geofysik;

    Sammanfattning : Two-dimensional (2-D) models of electrical resistivity are improved by jointly inverting radiomagnetotelluric (RMT) and direct-current resistivity (DCR) data or by allowing for displacement currents in the inversion of RMT data collected on highly resistive bedrock. Uniqueness and stability of the 2-D models are assessed with a model variance and resolution analysis that allows for the non-linearity of the inverse problem. LÄS MER

  3. 2. Airborne Gravity Gradient, Magnetic and VLF datasets : Case studies of modelling, inversion and interpretation

    Författare :Sayyed Mohammad Abtahi; Thomas Kalscheuer; Laust Pedersen; Jochen Kamm; Thorkild Rasmussen; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; VLF; gravity gradient; magnetic; airborne; inversion; non-uniqueness;

    Sammanfattning : Northern Sweden is one of the largest hosts for mineral resources in Europe and always has been an interesting area for researchers from various disciplines of Earth sciences. This dissertation is a comprehensive summary of three case study papers on airborne VLF, gravity gradient and magnetic data in the area. LÄS MER

  4. 3. Efficient Electromagnetic Induction Modelling : Adaptive mesh optimisation, advanced boundary methods and iterative solution techniques

    Författare :Laura M. Buntin; Thomas Kalscheuer; Gunilla Kreiss; Zhengyong Ren; Klaus Spitzer; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Applied geophysics; Electromagnetic theory; Numerical Modelling; Geo-Electromagnetics; Magnetotellurics; Controlled-source electromagnetics; Goal-oriented adaptive mesh refinement; Perfectly-matched layers; Iterative solution methods; Preconditioning; Geofysik med inriktning mot fasta jordens fysik; Geophysics with specialization in Solid Earth Physics;

    Sammanfattning : Forward modelling of electromagnetic induction data simulates the electric and magnetic fields within a computational domain for a given distribution of electromagnetic material properties and a given source of the electromagnetic field. The quantities of interest are the fields at receiver locations at the Earth's surface. LÄS MER

  5. 4. Three-dimensional forward modelling and inversion of controlled-source electromagnetic data using the edge-based finite-element method

    Författare :Paula Rulff; Thomas Kalscheuer; Michael Becken; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Applied geophysics; Controlled-source electromagnetics; Numerical modelling; Finite-element method; Geophysical inversion; Geofysik med inriktning mot fasta jordens fysik; Geophysics with specialization in Solid Earth Physics;

    Sammanfattning : Electromagnetic geophysical methods are applied to investigate anomalous subsurface structures exhibiting contrasts in electrical resistivity, as for example in mineral exploration or geothermal areas. When evaluating electromagnetic data, one big challenge is to account for full three-dimensional measurement setups and subsurface scenarios. LÄS MER

  7. 5. Natural and Controlled Source Magnetotelluric Data Processing and Modeling

    Författare :Chunling Shan; Thomas Kalscheuer; Laust Pedersen; Mehrdad Bastani; Thorkild Rasmussen; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Geophysics; Airborne Electromagnetic Method; Radio Magnetotellurics; Controlled Source Magnetotellurics; Electrical Resistivity Tomography; Moving Magnetotellurics; 2D inversion; 3D inversion;

    Sammanfattning : In this thesis, four studies using different geophysical electromagnetic methods are presented. In the first study dealing with airborne measurements, the noise response due to the rotation of the aircraft and the aircraft itself as a metallic conductive body on the Earth's electromagnetic response in very low frequency and low frequency band was investigated. LÄS MER