Sökning: "geofysik"

Visar resultat 16 - 20 av 192 avhandlingar innehållade ordet geofysik.

1. 16. 2D and 3D Seismic Surveying at the CO2SINK Project Site, Ketzin, Germany: The Potential for Imaging the Shallow Subsurface

   Författare :Sawasdee Yordkayhun; Christopher Juhlin; Charlotte Krawczyk; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Inversion; Traveltime tomography; 3D seismic surveys; Seismic velocity; Seismic source; CO2SINK project; Geophysics; Geofysik;

   Sammanfattning : Seismic traveltime inversion, traveltime tomography and seismic reflection techniques have been applied for two dimensional (2D) and three dimensional (3D) data acquired in conjunction with site characterization and monitoring aspects at a carbon dioxide (CO2) geological storage site at Ketzin, Germany (the CO2SINK project). Conventional seismic methods that focused on investigating the CO2 storage and caprock formations showed a poor or no image of the upper 150 m. LÄS MER

3. 17. Seismicity Analyses Using Dense Network Data : Catalogue Statistics and Possible Foreshocks Investigated Using Empirical and Synthetic Data

   Författare :Angeliki Adamaki; Roland Roberts; Beata Orlecka-Sikora; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Statistical Seismology; Earthquake Catalogue Statistics; Seismicity Patterns; Precursors; Foreshocks; Στατιστική Σεισμολογία; Κατάλογοι Σεισμών; Μοτίβα Σεισμικότητας; Πρόδρομα Φαινόμενα; Προσεισμοί; Geofysik med inriktning mot seismologi; Geophysics with specialization in Seismology;

   Sammanfattning : Precursors related to seismicity patterns are probably the most promising phenomena for short-term earthquake forecasting, although it remains unclear if such forecasting is possible. Foreshock activity has often been recorded but its possible use as indicator of coming larger events is still debated due to the limited number of unambiguously observed foreshocks. LÄS MER

4. 18. Simulating Earthquake Rupture and Near-Fault Fracture Response

   Författare :Billy Fälth; Björn Lund; Roland Roberts; Harald Hökmark; Eric Dunham; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Geofysik med inriktning mot seismologi; Geophysics with specialization in Seismology;

   Sammanfattning : Sweden is presently a low seismicity area where most earthquakes are small and pose no serious threat to constructions. For the long-term perspectives of safety assessments of geological repositories for spent nuclear fuel, however, the effects of large earthquakes have to be considered. LÄS MER

5. 19. Location and Relocation of Seismic Sources

   Författare :Ka Lok Li; Ólafur Gudmundsson; Roland Roberts; Ari Tryggvason; Lars Ottemöller; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Earthquake location; Earthquake relocation; Tremor location; Bayesian inversion; Correlation; Earthquake catalog; Iceland; Seismicity; Interferometry; Inverse theory; Volcanic tremor; Geofysik med inriktning mot seismologi; Geophysics with specialization in Seismology;

   Sammanfattning : This dissertation is a comprehensive summary of four papers on the development and application of new strategies for locating tremor and relocating events in earthquake catalogs.In the first paper, two new strategies for relocating events in a catalog are introduced. LÄS MER

7. 20. Analyses and Application of Ambient Seismic Noise in Sweden : Source, Interferometry, Tomography

   Författare :Hamzeh Sadeghisorkhani; Ólafur Gudmundsson; Ari Tryggvason; Roland Roberts; Frederik Tilmann; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Seismic interferometry; Ambient noise; Surface wave; Wave propagation; Inverse theory; Sweden; Geofysik med inriktning mot seismologi; Geophysics with specialization in Seismology;

   Sammanfattning : Ambient seismic noise from generation to its application for determination of sub-surface velocity structures is analyzed using continuous data recordings from the Swedish National Seismic Network (SNSN). The fundamental aim of the thesis is to investigate the applicability of precise velocity measurements from ambient noise data. LÄS MER