Sökning: "geophysics"

Visar resultat 16 - 20 av 183 avhandlingar innehållade ordet geophysics.

  1. 16. Natural and Controlled Source Magnetotelluric Data Processing and Modeling

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :Chunling Shan; Thomas Kalscheuer; Laust Pedersen; Mehrdad Bastani; Thorkild Rasmussen; [2014]
    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

  2. 17. Environmental and hydrogeological geophysics with applications in Thailand, Laos, and Sweden

    Detta är en avhandling från Luleå : Luleå tekniska universitet

    Författare :Kamhaeng Wattanasen; [2007]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Applied Geophysics; Tillämpad geofysik;

    Sammanfattning : This thesis presents applications of geophysical methods in the fields of environment and hydrogeology. In relation to environmental problems, two different geophysical surveys have been carried out; one to study an arsenic contaminated area in the southern Thailand (paper I) and a second to locate shallow faults in Quaternary sediments in an area around the Ongkharak Nuclear Research Centre, central Thailand (paper II). LÄS MER

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

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :Thomas Kalscheuer; Laust B. Pedersen; Christopher Juhlin; Roland Roberts; Heinrich Brasse; [2008]
    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; NATURAL SCIENCES Physics Other physics Geophysics; NATURVETENSKAP Fysik Övrig fysik 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

  4. 19. Seismics, 2D and 3D Inversion of Magnetotellurics Jigsaw pieces in understanding the Skellefte Ore District

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :María de los Ángeles García Juanatey; Ari Tryggavson; Ute Weckmann; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Magnetotellurics; 2D inversion; 3D inversion; hard rock seismics; mineral exploration; integrated geophysics; 4D modeling; Geofysik med inriktning mot fasta jordens fysik; Geophysics with specialization in Solid Earth Physics;

    Sammanfattning : The Skellefte District (SD) is one of the richest metallogenic mining areas in Sweden. The main deposits consist of volcanic-hosted massive sulphides (VHMS) rich in zinc, copper, lead, gold and silver, that have been explored and mined for more than a century. LÄS MER

  5. 20. Estimation of snow wetness using multi-offset ground penetrating radar towards more accurate estimates of snow water equivalent

    Detta är en avhandling från Luleå : Luleå tekniska universitet

    Författare :Nils Granlund; [2009]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Tillämpad geofysik; Applied Geophysics; Applied Geology; Tillämpad geologi;

    Sammanfattning : Measurements of snow water equivalent (SWE) constitute an important input to hydrological models used to predict snowmelt runoffs. The new generation of such models use distributed snow data, including distribution of SWE, as input, and rely on it for calibration and validation. LÄS MER