Ziegler, Moritz O. ; Seithel, Robin ; Niederhuber, Thomas ; Heidbach, Oliver ; Kohl, Thomas ; Müller, Birgit ; Rajabi, Mojtaba ; Reiter, Karsten ; Röckel, Luisa (2024)
Stress state at faults: the influence of rock stiffness contrast, stress orientation, and ratio.
In: Solid Earth, 2024, 15 (8)
doi: 10.26083/tuprints-00028031
Artikel, Zweitveröffentlichung, Verlagsversion
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Kurzbeschreibung (Abstract)
The contemporary crustal stress state is primarily driven by gravitational volume forces and plate tectonics. However, there are various smaller-scale sources such as geological structures and stiffness contrast that perturb stresses and deviate them from the regional pattern. For example, borehole stress analysis in numerous cases has revealed abrupt rotations of horizontal stress orientation of up to 90° when faults are crossed. Herein, we investigate the rotation of principal stress axes at a fault by means of a 2D generic numerical model. We focus on the near field of the fault and the damage zone with a fault parameterized as a rock stiffness contrast. A substantial influence of the far-field stress field in terms of the differential stress and in terms of the stress ratio RS=S₁/S_3 is shown. Furthermore, the contrast in material properties is the basis for any stress rotation, and in particular the stiffness is demonstrated to have a significant influence. Eventually, the impact of the angle between the fault strike and the orientation of SHmax is demonstrated. Our results show that the stress rotation is negatively correlated with the ratio of principal far-field stresses. A small angle between the far-field stress orientation and the fault facilitates stress rotation. A high contrast in rock stiffness further increases the stress rotation angle. Faults striking perpendicular to the maximum principal stress orientation experience no rotation at all. However, faults oriented parallel to the maximum principal stress orientation experience either no rotation or a 90° rotation, dependent on the ratio of principal stresses and the rock stiffness contrast. A comparison with observations from various boreholes worldwide shows that in general the findings are in agreement, even though the dip angle proves to have an influence on the stress rotation, in particular for shallow-dipping faults.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2024 |
| Autor(en): | Ziegler, Moritz O. ; Seithel, Robin ; Niederhuber, Thomas ; Heidbach, Oliver ; Kohl, Thomas ; Müller, Birgit ; Rajabi, Mojtaba ; Reiter, Karsten ; Röckel, Luisa |
| Art des Eintrags: | Zweitveröffentlichung |
| Titel: | Stress state at faults: the influence of rock stiffness contrast, stress orientation, and ratio |
| Sprache: | Englisch |
| Publikationsjahr: | 18 September 2024 |
| Ort: | Darmstadt |
| Publikationsdatum der Erstveröffentlichung: | 23 August 2024 |
| Ort der Erstveröffentlichung: | Göttingen |
| Verlag: | Copernicus Publications |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Solid Earth |
| Jahrgang/Volume einer Zeitschrift: | 15 |
| (Heft-)Nummer: | 8 |
| DOI: | 10.26083/tuprints-00028031 |
| URL / URN: | https://tuprints.ulb.tu-darmstadt.de/28031 |
| Zugehörige Links: | |
| Herkunft: | Zweitveröffentlichung DeepGreen |
| Kurzbeschreibung (Abstract): | The contemporary crustal stress state is primarily driven by gravitational volume forces and plate tectonics. However, there are various smaller-scale sources such as geological structures and stiffness contrast that perturb stresses and deviate them from the regional pattern. For example, borehole stress analysis in numerous cases has revealed abrupt rotations of horizontal stress orientation of up to 90° when faults are crossed. Herein, we investigate the rotation of principal stress axes at a fault by means of a 2D generic numerical model. We focus on the near field of the fault and the damage zone with a fault parameterized as a rock stiffness contrast. A substantial influence of the far-field stress field in terms of the differential stress and in terms of the stress ratio RS=S₁/S_3 is shown. Furthermore, the contrast in material properties is the basis for any stress rotation, and in particular the stiffness is demonstrated to have a significant influence. Eventually, the impact of the angle between the fault strike and the orientation of SHmax is demonstrated. Our results show that the stress rotation is negatively correlated with the ratio of principal far-field stresses. A small angle between the far-field stress orientation and the fault facilitates stress rotation. A high contrast in rock stiffness further increases the stress rotation angle. Faults striking perpendicular to the maximum principal stress orientation experience no rotation at all. However, faults oriented parallel to the maximum principal stress orientation experience either no rotation or a 90° rotation, dependent on the ratio of principal stresses and the rock stiffness contrast. A comparison with observations from various boreholes worldwide shows that in general the findings are in agreement, even though the dip angle proves to have an influence on the stress rotation, in particular for shallow-dipping faults. |
| Status: | Verlagsversion |
| URN: | urn:nbn:de:tuda-tuprints-280314 |
| Sachgruppe der Dewey Dezimalklassifikatin (DDC): | 500 Naturwissenschaften und Mathematik > 550 Geowissenschaften |
| Fachbereich(e)/-gebiet(e): | 11 Fachbereich Material- und Geowissenschaften 11 Fachbereich Material- und Geowissenschaften > Geowissenschaften 11 Fachbereich Material- und Geowissenschaften > Geowissenschaften > Fachgebiet Ingenieurgeologie |
| Hinterlegungsdatum: | 18 Sep 2024 11:37 |
| Letzte Änderung: | 19 Sep 2024 05:43 |
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| Suche nach Titel in: | TUfind oder in Google |
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- Stress state at faults: the influence of rock stiffness contrast, stress orientation, and ratio. (deposited 18 Sep 2024 11:37) [Gegenwärtig angezeigt]
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