Present-day stress field and deformation in eastern Austria
Abstract
We analysed fault plane solutions and borehole breakouts in the eastern part of the Eastern Alps and found a heterogeneous stress field which we interpret as a transition zone of three different stress provinces: the western European stress province with NW to NNW SH orientation and mainly strike-slip faulting regime; the Adriatic stress province with a radial stress pattern and thrust faulting to strike-slip faulting regime; and the Dinaric-Pannonian stress province with NE SH orientation and strike-slip faulting regime. The western Pannonian basin seems to be a part of the transition zone with WNW to NW SH orientation. A stress regime stimulating strike-slip faulting prevails in the Eastern Alps. The south Bohemian basement spur as a major tectonic structure with a high rheological contrast to surrounding units has a strong influence on the stress field and exhibits the highest seismicity at its tip due to stress concentration. From a constructed vertical stress orientation profile we found stress decoupling of the Northern Calcareous Alps from the underlying European foreland. Both the Molasse and the Flysch-Helvetic zone are considered as candidates for decoupling horizons due to stress orientation observations and due to their rheological behaviour. From seismological and rheological data, we suggest a horizontal stress decoupling across the Eastern Alps caused by a weakened central Alpine lithosphere.
- Publication:
-
International Journal of Earth Sciences
- Pub Date:
- October 1999
- DOI:
- 10.1007/s005310050283
- Bibcode:
- 1999IJEaS..88..532R
- Keywords:
-
- Key words Eastern Alps;
- South Bohemian basement spur;
- Fault plane solutions;
- Borehole breakouts;
- Stress field;
- Stress decoupling;
- Present-day deformation