Rurrand fault.
Composite source DECS001 corresponds to the west-dipping Rurrand fault south of the intersection with the Lövenich/Kast fault (DECS002). The Rurrand fault has been mapped in detail by Ahorner (1962), and consists of three sections separated by stepovers (Figure S4): the northern (Linnich) section, central (Jülich) section, and southern (Düren) section. The central section is shifted ~2 km east compared to the northern and southern sections. The stepover widths are probably too small to define segment boundaries, and it is not inconceivable that the entire Rurrand fault source as defined here could rupture in a single segment. According to the map of Ahorner (1962), there is another west-dipping fault further south, the Kirspenich fault (DECS008). However, the gap in between is ~8 km, and a few km to the west of this gap, the east-dipping Stockheim fault (DECS007) is situated. It is therefore unlikely that the Rurrand and Kirspenich faults are part of the same source.
| Fault section | Trench site | Year | Institute | Reference |
|---|---|---|---|---|
| Jülich section | Jülich-Stallbusch | 1999 | GDNRW/ROB | Lehmann et al. (2001); Vanneste and Verbeeck (2001) |
| Düren section | Merzenich | 2004 | GDNRW | Skupin et al. (2008) |
The main source of information on vertical offsets on the faults belonging to the NE border fault zone in the German part of the LRG is again the map of Ahorner (1962). We used the same procedure as outlined for DECS005 to determine the minimum and maximum vertical displacement rates. We thus obtained a vertical displacement rate of 0.020 – 0.038 mm/yr for the Rurrand fault. In a trench across the Rurrand fault, Vanneste and Verbeeck (2001) observed at least 3.1 m of vertical displacement of the top of a loess unit in which an OSL date of 43.4 ± 12.6 kyr BP was obtained (Lehmann et al., 2001). This would imply a vertical displacement rate of 0.055 – 0.100 mm/yr, which is significantly higher than the long-term rate for this fault. Better age control is necessary, however, to corroborate this result, so we adopt the long-term rate for the time being.
| ID | Type of evidence | Offset (m) | Time period | Deformation rate (mm/yr) | Reference |
|---|---|---|---|---|---|
| 17 | Displacement of base of “Ältere Hauptterrasse” of the Rhine R. |
Mean: 51.1 (n=9) Max: 76 |
Since 2.0 – 2.58 Ma | 0.020 – 0.038 | Based on data from Ahorner (1962) |
| 18 | Observed fault displacement in paleoseismic trench | ≥ 3.1 | Since 43.4 ± 12.6 kyr | 0.055 – 0.100 | Based on data from Vanneste and Verbeeck (2001) |
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