In situ stress data from the Jura Mountains — new results and interpretation

Abstract

Recently completed in situ stress measurements using the borehole slotter at 33 new test sites within the Swiss and French Jura Mountains are presented. When combined with previously published stress data, these new measurements allow a detailed description of the contemporary state of stress in this fold‐and‐thrust belt and the adjacent foreland. The data now allow the recognition of five stress provinces, within which two general and different orientations of maximum horizontal stress SH can be distinguished: the Central and the Southwest Provinces, with a NNW–SSE to NNE–SSW orientation, and the East, Northwest and Southeast Provinces, orientated E–W to NW–SE. Each province has its own characteristic orientation. Measurements in three study areas are presented for comparison with already published acoustic anisotropy measurements, borehole breakout data, overcoring tests and triangulation measurements. The results show a generally good agreement with the new borehole slotter measurements. The tectonic implications of these stress data are discussed in terms of a large‐scale stress reorientation of the NW–SE orientated contemporary Central European stress field in the foreland of the western Alpine arc.