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and S direction abruptly turn to the east. This change probably caused by the presence of a tectonic structure.
Figure 6.7 Graphical representation of the azimuth orientation of the slopes in the study area.
The data from the interpretation of the Slope distribution Map and the Aspect Map are presentesd in the Morphotectonic map in the next paragraph.
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Figure 6.8 Stream order classification map-Strahler classification (GGRS87). The yellow lines represent the reconstructed streams with the Global Mapper V13 software. . This map is also presented in the Appendix II.
Thus, their flow changes due to the uplift that Dionysos fault engenders in the wider area.Generally the flows into these basins are accumulated towards north,south and east. The maximum stream branch that is documented is a fifth-order stream (drainage basins N.1 and N.2).
Drainage basin N.1 ( Fig. 6.8 ) covers an area of 97 Km2 in the SE is draining the southern slopes of SE Penteli to the Evoikos Gulf in the east. This flow direction changes abruptly from approximately N-S and NW-SE to E where Megalo Rema and Rema Rafinas are joined (fifth-order stream). This change might concides with the existance and the fanctioning of a tectonic structure.
The N-S and NW-SE flows are perpendicular to the Dionysos fault, which is common for normal faults where the tilted footwall results into perpendicular flow direction, that drain the footwall away from the hangingwall (Gawthorpe and Hurst., 1993).
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Drainage basin N.2 ( Fig. 6.8 ) covers an area of 45 Km2 in the central part of the study area draining the central-northern slopes of Penteli to the north, where a third-order stream and a fourth-order stream join Kimpitougios stream ( fourth-order stream). The flow direction then changes from N-S to E in a fifth-order stream. In the foothills of northern-central Penteli we confirm headward erosion within the footwall catchments that drain across the fault into the hangingwall producting perpendicular fault flow directions. In the Dionysovouni slopes, fault parallel flow directions are confirmed due to hangingwall subsidence trending NW-SE ( Fig. 6.9 ).
Figure 6.9 Part of the reconstructed drainage pattern in the center of Dionysos fault.
Drainage basin N.3 ( Fig. 6.8 ) covers an area of 65 Km2 in the southwestern part of Penteli draining the SW slopes to the SSW.
Drainage basin N.4 ( Fig. 6.8) covers an area of 7 Km2 in the Petroti hill draining the slopes to the Evoikos Gulf.
Drainage basin N.5 ( Fig. 6.8) covers an area of 14 Km2 west of the Nea Makri, with an W-E flow direction draining the northeastern slopes of Penteli and the southern slopes of Petroti hill to the Evoikos Gulf.
Drainage basin N.6 ( Fig. 6.8) covers an area of 11 Km2 with a W-E flow direction that drains the nortestern slopes of Penteli to the Evoikos Gulf. The flow direction is perpendicular to the fault trace.
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Drainage basin N.7 –Kifissos basin ( Fig. 6.8) covers a total area (the total area does not depict in the map) of 112 Km2 in the west with a NNE-SSW flow direction that drains the Athens Plain from the southern slopes of Parnitha and the SW slopes of Penteli, to the south (Saronikos Gulf). Likewise the other drainaige basins the echo of the Dionysos fault is clear. Particularly (Fig. 6.9) the tilted footwall results perpendicular N-S flow directions that progress into fault parallel flow direction due to the hangingwall subsidence in a E-W flow direction.
In order to trace the Dionysos fault influence to the catchments that drain across the fault into the hangingwall 21 longitudinal river profiles ( Fig. 6.10 ) had been constructed. Although Whittaker et al., 2008; and Papanikolaοu et al.,2013 suggest that the selected rivers should discharge a drainage basin larger than 10km2 above fault and the upstream length should be at least 5 km those restrictions were not aplicable in the study area.
Figure 6.10 Catchments that drain across the Dionysos fault where river profiles where performed.
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However those profiles afforded pure outecomes lengthwise of the Dionysos fault. The majority of the river profiles depict convex to linear shape that correspond to areas where active tectonic processes exist. Quantattive analsis of the river profiles showed significant differences in convexity along the Dionysos fault strike. In the first 1,2,3 catchments ( Table 6.1) that are located towards the western part of the Dionysos fault where no talus cones were detected and the throw is smaller, the convex reach is approximately at 440 m in addition with the catchments that are located in the central part of the Dionysos fault N.4,5,6,7,8,9,10 that the convex reach is at ~560 m and coincides with the Dionysos fault trace.
Table 6.1 River longitudinal profiles and additional information for each of the catchments such as,number, Strahler stream order classification and the downstream distance.
Number Strahler Stream Order Classification
L
(meters) River Profile
1 1st 568
2 1st 462
3 2nd 385
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4 1st 1660
5 1st 878
6 1st 870
7 2nd 382
8 2nd 615
9 2nd 289
10 1st 1053
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11 2nd 1354
12 2nd 1146
13 1st 882
14 3rd 402
15 1st 453
16 1st 594
17 1st 640
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18 1st 806
19 2nd 560
20 2nd 670
21 3rd 2078
The data from the interpretation of the Drainage pattern will be presentesd in the Morphotectonic map in the next paragraph.
Planation surfaces
Planation surfaces that develop in the study area are divided into two different types with angles between 0-5 °:
I. Depositional planation surfaces II. Erosional planation surfaces
In the first category are included, inter alia, the coastal area in Nea Makri with altitude up to 100 m, the basinal area of Dionysos with altitudes from 300 m to 500m and south of Nea Penteli where planation surfaces appear in less than 300 m altitude.
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Figure 6.11 Planation surfaces of the wider Penteli area (GGRS87). With different colors is reflected the different altitudes that planation surfaces both depositional an erosional are located.
On the second category of planation surfaces are inculed , inter alia, the Penteliko ridge surfaces with altitude from 800m to 1061m that are tilted to the south and west of Xylokeratea with altidute 500m tilting to the east. Those planation surfaces generally direct parallel to the Dionysos fault zone and their tilting is due to the footwall uplift.
Figure 6.12 Deep incision map in the Penteli mt (GGRS87).
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The geometry and the erosion of the river network is the result of the strong uplift that the Dionysos fault causes in the Penteli mt. In particular deep incision zones, are directly linked with the tectonic regime of the region and mostly are developing vertically in the Dionysos fault ( Fig. 6.12). The combination of the erosion with the active character of the fault might cause the establishment of landslides or instabilities. A lanslide in mica schists has been identified during the fieldwork east of Rea (see geological map- Fig.
5.25).