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Showing result 1 - 5 of 19 swedish dissertations matching the above criteria.

2. 1. Inversion and Joint Inversion of Electromagnetic and Potential Field Data

   Author : Jochen Kamm; Ari Tryggvason; Laust B Pedersen; Mehrdad Bastani; Douglas Oldenburg; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Inversion; Electromagnetic methods; Joint inversion; Potential Field methods; Inversion; Elektromagnetische Verfahren; Joint-Inversion; Potentialverfahren; Geofysik med inriktning mot fasta jordens fysik; Geophysics with specialization in Solid Earth Physics;

   Abstract : In this thesis, four inversion problems of different scale and difficulty are solved. Two of them are electromagnetic inverse problems. Two more are joint inversion problems of potential field data and other types of data. READ MORE

4. 2. Joint inversion and integration of multiple geophysical data for improved models of near-surface structures

   Author : Shunguo Wang; Alireza Malehmir; Mehrdad Bastani; Thomas Kalscheuer; Mark Everett; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; joint inversion; ERT; RMT; CSRMT; boat-towed; tomography; Geofysik med inriktning mot fasta jordens fysik; Geophysics with specialization in Solid Earth Physics;

   Abstract : Geophysical methods are non-invasive and allow an effective way of understanding subsurface structures and their physical properties. One of the main challenges is the often non-uniqueness of the geophysical models and that several different models can explain a dataset to an agreeable fit. READ MORE

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

   Author : Thomas Kalscheuer; Laust B. Pedersen; Christopher Juhlin; Roland Roberts; Heinrich Brasse; Uppsala universitet; []
   Keywords : 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;

   Abstract : 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. READ MORE

6. 4. Controlled Source Radiomagnetotelluric (CSRMT) Applications in Environmental and Resource Exploration

   Author : Nazli Ismail; Laust Pedersen; Bulent Tezkan; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Magnetotelluric; radio magnetotelluric; controlled-source tensor magnetotelluric; plane wave; near surface geophysics; sediment; fracture zone; inversion; forward modelling; near field effect; two-dimensional model; three-dimensional model; resolution; Geophysics; Geofysik; Earth Sciences with Specialization Environmental Analysis; geovetenskap med inriktning mot miljöanalys; Hydrology; hydrologi; mineralogi; petrologi och tektonik; Mineral Chemistry; Petrology and Tectonics;

   Abstract : An integrated use of radio magnetotelluric (RMT) and controlled source tensor magnetotelluric (CSTMT) measurements, the so-called CSRMT method, has been employed in environmental and resource exploration studies. A number of case histories, including a groundwater investigation in glacial deposits, a study of fracture zones for geotechnical purposes and a mining exploration study of a copper deposit, are presented in this thesis in order to illustrate the usefulness and capability of the CSRMT method. READ MORE

7. 5. Investigating Time-Varying Processes Using Seismicity and Time-Dependent Tomography

   Author : Alex Hobé; Ari Tryggvason; Olafur Gudmundsson; Roland Roberts; Nicholas Rawlinson; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Time-Dependent Tomography; Joint Inversion; Geothermal Energy; Volcanotectonics; Seismic Unrest; Fagradalsfjall Eruption; Geofysik med inriktning mot seismologi; Geophysics with specialization in Seismology;

   Abstract : Our global society is affected by, and makes use of, many time-varying processes. Processes related to geothermal energy and CO2 sequestration can help mitigate climate change and reduce the number of premature deaths (millions annually) due to air pollution from fossil fuels. READ MORE