Signatura: 51192
ISBN: 9783908440369

Nakladatelské údaje: Zürich : Schweizerischen Geodätischen Kimmission , 2014
Edice: Geodätisch-geophysikalische Arbeiten in der Schweiz
Anotace: Schwitzerland is a region with relatively low seismicity compared to other litospheric subduction zones. However, from historic earthquakes it is known that events with large magnitudes, above 6, have occurred. A major task was to extract the tectonic pattern of the velocity field based on GNSS campaign type data (CHTRF 2010 solution) given the fact that the noise level and local influences are within the same order of magnitude as the deformation occurring. The introduction of the adaptive least-squares collocation (ALSC) and its enhancement to determine the tectonically driven deformation field allowed to extract a reliable kinematic model for Switzerland. The final solution consists of the velocity field and its derivative, the strain rate field. Due to the relatively high density of measurement points, re-measured three or more times, the field could be retrieved from the data set. The horizontal velocities are mostly below 1mm/yr and the uplift rates, determined from precise leveling, between 0 and 1,5 mm/yr. The deformation rates deduced amount to 25 nstrain/yr. The thin plate model allowed to estimate also the vertical strain rate which was not possible to retrieve by the collocation technique alone. This is due to the lack of missing measurements within the crust since all leveling and GNSS measurements are performed on the surface. The comparison of the restrain rate field with seismological data showed a good accordance. The horizontal strain field confirms a compression of 15 nstrain/yr perpendicular to the Alpine chain. In the canton Valais seismic recordings observed extensional stress regimes. The collocation technique could reproduce the extension and retrieved a strain rate of 20 nstrain/yr. at the boundary of the study area uncertainties exists because of missing data outside Schwitzerland. This is a particular problem in the city of Basel, which lies at the southern end of the Upper Rheingraben. The 3-D strain rate tensor, using the thin plate model, has shown mostly similar fault plane solutions as the one obtained from earthquake analysis. The same is valid for the strain rate energy compared with the seismic energy released by earthquakes. The highest strain energy density is found in the eastern and western part of the Swiss Alps. This project has been funded by swisstopo and the Geodesy and Geodynamcics Lab, ETH Zurich. The work which was carried out for the project COGEAR was financed by the Competence Center Environment and Sustainability of the ETH Domain (CCES).
Anotace: Schwitzerland is a region with relatively low seismicity compared to other litospheric subduction zones. However, from historic earthquakes it is known that events with large magnitudes, above 6, have occurred. A major task was to extract the tectonic pattern of the velocity field based on GNSS campaign type data (CHTRF 2010 solution) given the fact that the noise level and local influences are within the same order of magnitude as the deformation occurring. The introduction of the adaptive least-squares collocation (ALSC) and its enhancement to determine the tectonically driven deformation field allowed to extract a reliable kinematic model for Switzerland. The final solution consists of the velocity field and its derivative, the strain rate field. Due to the relatively high density of measurement points, re-measured three or more times, the field could be retrieved from the data set. The horizontal velocities are mostly below 1mm/yr and the uplift rates, determined from precise leveling, between 0 and 1,5 mm/yr. The deformation rates deduced amount to 25 nstrain/yr. The thin plate model allowed to estimate also the vertical strain rate which was not possible to retrieve by the collocation technique alone. This is due to the lack of missing measurements within the crust since all leveling and GNSS measurements are performed on the surface. The comparison of the restrain rate field with seismological data showed a good accordance. The horizontal strain field confirms a compression of 15 nstrain/yr perpendicular to the Alpine chain. In the canton Valais seismic recordings observed extensional stress regimes. The collocation technique could reproduce the extension and retrieved a strain rate of 20 nstrain/yr. at the boundary of the study area uncertainties exists because of missing data outside Schwitzerland. This is a particular problem in the city of Basel, which lies at the southern end of the Upper Rheingraben. The 3-D strain rate tensor, using the thin plate model, has shown mostly similar fault plane solutions as the one obtained from earthquake analysis. The same is valid for the strain rate energy compared with the seismic energy released by earthquakes. The highest strain energy density is found in the eastern and western part of the Swiss Alps. This project has been funded by swisstopo and the Geodesy and Geodynamcics Lab, ETH Zurich. The work which was carried out for the project COGEAR was financed by the Competence Center Environment and Sustainability of the ETH Domain (CCES).


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