Slip Tendency analysis

The occurrence of earthquakes should be avoided in the area of nuclear waste repositories. Since earthquakes preferentially occur on tectonic faults when they are reactivated under the right stress field, an estimation about the reactivation potential of the faults is important. Such an estimation is provided by the so-called slip tendency, which is calculated from the ratio of the maximum resolved shear stress to the normal stress on the fault surface. The SpannEnD-Germany model provides the stress tensor needed to calculate the shear and normal stresses.

In addition, information is required on the geometry of the tectonic faults for which the slip tendency is to be calculated. Based on various criteria, 60 faults were identified that are particularly relevant in the context of the SpannEnD project. Simple geometries were created for these faults depending on whether they are normal faults, thrust faults or strike slip faults.


Simple geometries were created for the 60 selected faults. The faults extend to the base of the lower crust.
The slip tendency was calculated for the 60 selected faults. It is shown in colour-coded form. The calculation was based on the assumption of hydrostatic pore pressure.

A comparison of different regions reveals a heterogeneous distribution of the slip tendnecy throughout Germany. One prominent example is the Upper Rhine Graben, that shows a considerably higher slip tendency than the North German Basin. Faults that are oriented in a NNE – SSW direction generally show the highest slip ten dency for all analyzed fault types. In contrast, a ENE – WSW orientation generally generatest he lowest slip tendencies for all three fault types.

The plots show the Slip Tendency (TSeff) as a function of fault orientation between 0° and 180°for the three fault types (NF: normal faults, TF: thrust faults, SS: strike-slip faults). The data points are colored by the stress regime that they are subjected to. The median of the slip tendency in 10° intervals is shown alongside the individual data points.

References:

Shapefiles Countries: © EuroGeographics for the administrative boundaries

Morris, A., Ferrill, D. A. and Henderson, D. B.: Slip-tendency analysis and fault reactivation. Geology, 24(3), 275-278. https://doi.org/10.1130/0091-7613(1996)024%3C0275:STAAFR%3E2.3.CO;2, 1996.

Publications:

Röckel, L., Müller, B., Ahlers, S., Reiter, K., Hergert, T., Henk, A., Heidbach, O., and Schilling, F.: 3D fault sets of Germany and adjacent areas (v1), https://doi.org/10.5445/IR/1000143465, 2022.

Röckel, L., Ahlers, S., Müller, B., Reiter, K., Heidbach, O., Henk, A., Hergert, T., and Schilling, F.: The analysis of slip tendency of major tectonic faults in Germany, Solid Earth, 13, 1087–1105, https://doi.org/10.5194/se-13-1087-2022, 2022.

Contact: Luisa Röckel