Sandgewand fault.
Composite source DECS005 corresponds with the east-dipping Sandgewand fault. This fault is situated more than 6 km east of NLCS002 (Figure S3). Towards the NW, the Sandgewand fault bends westward according to the maps of Ahorner (1962) and Felder et al. (1989). The latter authors connect the Sandgewand fault with the NW-SE trending Koningsbosch fault. However, the throw of this fault is down to the west, so we consider it as a secondary, antithetic fault to the Feldbiss fault, and thus part of source NLCS002. Felder et al. (1989) draw another east-dipping fault (the 1st NE main fault) in between the Koningsbosch and Feldbiss faults which bends left to the NW, similar to the Sandgewand fault. However, the distance to the Feldbiss fault is only 2 to 3 km, so we consider it to belong to source NLCS002 as well. The bend in the north, which is ~4 km wide, thus defines the northern limit of DECS005. Towards the south, the Sandgewand fault terminates at approximately the same latitude as the Münstergewand fault section of NLCS002.
None
For the faults in Germany that are part of the SW border fault zone (DECS005, DECS006, and DECS007), the main source of information is the map of Ahorner (1962), reporting the displacement of the base of the Upper Main Terrace Sequence. This marker horizon is generally considered to have an age of 2.58 Ma. However, we discussed above that at least in the border area with the Netherlands, younger terraces are present. We therefore consider the age of the marker horizon to be uncertain, between 2.0 and 2.58 Ma. Ahorner (1962) reported several vertical offsets along the fault traces he mapped. Where different fault sections belonging to the same seismic source are overlapping, we summed their offsets along a line perpendicular to the fault. In general, offsets decrease rapidly towards the fault tips. These values are thus not really representative of the minimum offset, and instead we used the mean offset as the minimum value. The maximum vertical displacement rate then corresponds to the maximum offset divided by the minimum age (2.0 Ma), and the minimum vertical displacement rate corresponds to the mean offset divided by the maximum age (2.58 Ma). Thus, we obtain a vertical displacement rate of 0.010 – 0.017 mm/yr for DECS005.
| ID | Fault section | Offset (m) | Time period | Deformation rate (mm/yr) | Reference |
|---|---|---|---|---|---|
| 25 | Displacement of base of “Ältere Hauptterrasse” of the Rhine R. |
Mean: 25.4 (n=5) Max: 33 |
Since 2.0 – 2.58 Ma | 0.010 – 0.017 | Based on data from Ahorner (1962) |
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