Recent stress field and neotectonics in the Eastern Jura Mountains, Switzerland

Becker, Arnfried; Blümling, P.; Müller, W.H.

doi:10.1016/0040-1951(87)90112-0

Cited by 31 publications

(15 citation statements)

References 6 publications

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“…As a result of stress measurements by overcoring techniques in six boreholes, the observations of breakouts in a further five, Becker et al (1987) conclude that 'in the northern part of central Switzerland the NW-SE orientation of the maximum horizontal (compressive) stress (SH) which is characteristic for Central Europe was observed only in the crystalline basement. In the Folded Jura and south of it in one well the greatest principal horizontal stress above the Triassic decollement horizon is oriented approximately in a N-S to NNE-SSW direction'.…”

Section: Discussionmentioning

confidence: 91%

Crustal strain in Switzerland 1870-1970

Reilly¹,

Gubler²

1990

Geophysical Journal International

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S U M M A R YThe rate of horizontal crustal deformation in western Switzerland has been determined from a comparison of two triangulation surveys, centred approximately on the epochs of 1872 and 1912, and a trilateration survey made around 1970. A heterogeneous strain model was needed to fit these data, and yielded a rate of (tensor) shear strain of about 0.10 f 0.02 prad yr-' in central Switzerland, with the axis of maximum relative shortening (compression) aligned approximately NW-SE, and the magnitude of the shear-strain rate increasing to the SE. Along the chain of the Jura, the shear-strain rate is about 0.05 *0.02pradyr-l, with the axis of maximum relative shortening aligned NE-SW, parallel to the chain itself. This distribution of shear-strain rate is consistent with a complex bending in the horizontal plane, in which the (concave) normals to the axes of maximum bending rate lie in the NW quadrant (i.e. in the opposite sense to the present curvature of the Jura).

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Section: Discussionmentioning

confidence: 91%

Crustal strain in Switzerland 1870-1970

Reilly¹,

Gubler²

1990

Geophysical Journal International

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“…Second, it shows that at least one directly measurable attribute of this stress field reflects stress conditions at greater seismogenic depths, at least where prominent detachments are absent [e.g., Becker et al, 1987;Seeber and Armbruster, 1987]. First, it demonstrates that the dominant stress constituent present in a wide range of rock types at shallow depths reflects contemporary tectonic processes.…”

Section: Introductionmentioning

confidence: 99%

Appalachian Stress Study: 3. Regional scale stress variations and their relation to structure and contemporary tectonics

Evans¹

1989

J. Geophys. Res.

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Using commercial hydrofracture data to supplement published stress data, we map regional variations in least horizontal stress magnitude (Sh) and orientation within the Paleozoic sediments of the Appalachian Plateau. Systematic trends revealed by the data are examined for correlations with structure (the study area includes a prominent salt detachment) and tectonic history. The dominant stress component present at all depths (including basement) throughout the region is ENE oriented compression and is most likely of tectonic origin. No deviations from this rule are found that are statistically significant. Near‐surface (<600 m) stresses are consistently greater than the overburden with “strike‐slip” regime conditions prevailing below. However, where the Salina salt beds are present, “thrust” regime conditions extend deeper, reaching the salt in most places where data are available (limited to where the salt is shallower than 1.5 km). At the salt, a discontinuity in the trend of Sh with depth marks the abrupt transition to the underlying strike‐slip regime characterized by least stress ratios (i.e., Rh = Sh/Sv) in the range 0.5–0.7 and extending to basement. The comparatively high stress found above the salt may reflect a difference between the strain histories of the overlying and underlying sections facilitated by mechanical decoupling by the salt and perhaps includes a component of stress remnant from NW oriented Alleghanian shortening of the upper section. The lower (subsalt) stress regime extends beyond the eastern salt margin and displays remarkable uniformity over distances of hundreds of kilometers. This is particularly evident across Ohio, where an Rh value of 0.6±0.05 appears valid down to basement. North of Ohio, values increase markedly, whereas to the south of the salt pinch‐out, in West Virginia and eastern Kentucky, values as low as 0.35 are found in Devonian shales at 1–1.5 km depth, although values deeper in the section may be higher. The northward increasing trend can be reasonably well modeled as the effect of persisting lithospheric flexure due to the Pleistocene ice sheet. However, flexure was much greater in the past, and as Devonian shales in south Ohio/West Virginia are currently only marginally stable, a modest increase over the present flexure would be expected to cause shear failure. This suggests that the very low stress in the shales of south Ohio/West Virginia is of different origin and more recent than the Pleistocene.

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“…1986], detachments [Becker et al, 1987;Evans, 1989], and volcanic intrusions [Haimson and Rummel, 1982] as well as material property variations [Warpinski et al, 1983]. Yet despite the potential for complexity there can be little doubt that the pattern of stress variation contains valuable information regarding the nature of contemporary loading and those events in the rocks past which have left some imprint there are few studies which feature sampling of the stress field in both the spatial extent and detail necessary to reveal clearly systematic relationships between stress and lithology.…”

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confidence: 99%

Appalachian Stress Study: 1. A detailed description of in situ stress variations in Devonian shales of the Appalachian Plateau

1989

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We describe an experiment to measure variations in the state of stress within a horizontally bedded Devonian shale/sandstone/limestone sequence in western New York. A total of 75 stress measurements were made in three wells a kilometer or so apart using a wireline‐supported hydraulic‐fracturing system. The stress profiles indicate that a major drop in horizontal stress level occurs in the generally massive shales. This drop occurs principally across the lowermost member of a group of sand beds and corresponds to an offset in Sh and SH of 3.5 and 9 MPa, respectively. Above the sands, “thrust” regime conditions prevail, although the amount by which Sh exceeds Sv is undetermined since instantaneous shut‐in pressures (ISIPs) were clipped at the level of Sv due to fracture rotation. Below the sands, the regime is strike slip with both horizontal stresses showing lateral uniformity despite substantial variations in topography. The magnitude of Sh in the sand beds themselves and a lower limestone remains at least as great as Sv despite the decline in shale stress. Hence stress contrasts between these beds and neighboring shales become pronounced with depth. The contrast in Sh and SH between the lowermost sand and the immediately underlying shale is at least 6 and 14.5 MPa, respectively. SH levels in the lower strike‐slip regime are about 1.75 times greater than Sh and are less than the value required to initiate slippage on favourably oriented frictional interfaces. For the upper thrust regime and the sand and limestone beds, however, the inferred lower bound on SH is close to the slippage threshold for a Coulomb friction coefficient of 0.6. The orientation of SH is ENE with a standard deviation of 20°. Fracture traces were usually splayed, occasionally spanning 30° of well bore. No systematic correlation between mean orientation and lithology is evident. Significantly different orientations were obtained for adjacent tests in which almost identical ISlPs were observed, suggesting that the fractures quickly reorient themselves to propagate normal to the least principal stress direction. Similarly, vertical traces were observed in those tests where ISIPs apparently reflect Sv, suggesting that rotation to horizontal was rapid.

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Recent stress field and neotectonics in the Eastern Jura Mountains, Switzerland

Cited by 31 publications

References 6 publications

Crustal strain in Switzerland 1870-1970

Crustal strain in Switzerland 1870-1970

Appalachian Stress Study: 3. Regional scale stress variations and their relation to structure and contemporary tectonics

Appalachian Stress Study: 1. A detailed description of in situ stress variations in Devonian shales of the Appalachian Plateau

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