Search for dissertations about: "Geophysics"

Showing result 16 - 20 of 207 swedish dissertations containing the word Geophysics.

  1. 16. 3D Geophysical and Geological Modeling in the Skellefte District: Implications for Targeting Ore Deposits

    Author : Alireza Malehmir; Ari Tryggvason; Christopher Juhlin; Bernd Milkereit; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Geophysics; Seismic reflection; Hardrock; VHMS deposits; Potential field; 3D geologic model; Skellefte District; Geofysik;

    Abstract : With the advancements in acquisition and processing of seismic reflection data recorded over crystalline rocks, building three-dimensional geologic models becomes increasingly favorable. Because of little available petrophysical data, interpretations of seismic reflection data in hardrock terrains are often speculative. READ MORE

  2. 17. Statistical Seismology Studies in Central America : b-value, seismic hazard and seismic quiescence

    Author : David Aníbal Monterroso Juárez; Ota Kulhánek; Stefan Wiemer; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Geophysics; b-value; seismic hazard; Monte Carlo; seismic quiescence; Central America; stress; Geofysik; Geophysics; Geofysik;

    Abstract : The present thesis collects results of research applying theory and methods of statistical seismology to the seismicity of Central America, a region with a complex tectonic setting controlled by the interaction of four major plates, namely the Caribbean, Cocos, Nazca and North American plates.Three different earthquake catalogues were used for studies focused on stress in a tectonic volume, seismic hazard maps and seismicity patterns (precursors), covering the region 94ºW to 81ºW and 5ºN to 20ºN. READ MORE

  3. 18. Analyses of Seismic Wave Conversion in the Crust and Upper Mantle beneath the Baltic Shield

    Author : Sverker Olsson; Roland Roberts; Hans Thybo; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Geophysics; converted waves; Moho; upper mantle; Baltic Shield; tomography; anisotropy; receiver function; Geofysik;

    Abstract : Teleseismic data recorded by broad-band seismic stations in the Swedish National Seismic Network (SNSN) have been used in a suite of studies of seismic wave conversion in order to assess the structure of the crust and upper mantle beneath the Baltic Shield. Signals of seismic waves converted between P and S at seismic discontinuities within the Earth carry information on the velocity contrast at the converting interface, on the depth of conversion and on P and S velocities above this depth. READ MORE

  4. 19. A Broad View on the Interpretation of Electromagnetic Data (VLF, RMT, MT, CSTMT)

    Author : Behrooz Oskooi; Laust Börsting Pedersen; Thorkild Mack Rasmussen; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Geophysics; Airborne; azimuthal anisotropy; CSTMT; distortion; EM; geothermal; Hengill; mineralization; MT; peaker; resolution; RMT; tipper; tensor VLF; VLF; Geofysik; Geophysics; Geofysik;

    Abstract : The resolution power of single Very Low Frequency (VLF) data and multi-frequency Radiomagnetotelluric (RMT) data in delineating conductive structures typical for the sedimentary cover and crystalline basement in Scandinavia is studied with a view to future developments of the technique to increasing the frequency range into the LW radio band. Airborne and ground VLF data are interpreted and correlated with RMT measurements made on the ground to better understand the resolution power of VLF data. READ MORE

  5. 20. Integrated geophysical-geochemical methods for archaeological prospecting

    Author : Kjell Persson; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Geophysics; geophysical; geochemical; prospecting; archaeology; electric; magnetometric; Geofysik; Geophysics; Geofysik;

    Abstract : A great number of field measurements with different methods and instruments were conducted in attempts to develop a method for an optimal combination of various geochemical and geophysical methods in archaeological prospecting. The research presented in this thesis focuses on a study of how different anthropogenic changes in the ground can be detected by geochemical and geophysical mapping and how the results can be presented. READ MORE