Geology and Landslide Investigations in and Around the Cetin Dam Site


PERİNÇEK D.

TURKIYE JEOLOJI BULTENI-GEOLOGICAL BULLETIN OF TURKEY, cilt.59, ss.167-209, 2016 (ESCI İndekslerine Giren Dergi) identifier

  • Cilt numarası: 59 Konu: 2
  • Basım Tarihi: 2016
  • Dergi Adı: TURKIYE JEOLOJI BULTENI-GEOLOGICAL BULLETIN OF TURKEY
  • Sayfa Sayıları: ss.167-209

Özet

\Purpose of this study is to locate the landslides that can threaten the settlement areas around the Cetin dam reservoir is situated in vicinities of Pervari town of Siirt city. The Cetin Dam is going to be constructed in Botan Cayi (Ulu Cay) valley. The Cetin dam crest, reservoir areas are all located on allochthonous units. The Maden Complex is situated between the slices of the metamorphic rocks. Very steep inclination of the valley slopes are among the significant causes of the landslides. The frequency of the landslides increases when this feature is combined with the presence of the Maden Complex. Another reason triggering the landslides is the earthquakes. The reason why the slope inclination is steeper along Botan Cayi River is the tectonism which affected the region since the Middle Miocene. Among the most important numerous data that shows that the region is uplifting continuously are elevated erosional surface of the old rivers and the terraces can be counted as evidence of uplifting. These features provide important evidences to understand the relative ages of the landslides. The uplifting causes an increase in slope inclination. As the inclination of the slopes increase, new and younger landslides occur in debris of the older landslides. It was observed in many places that the material sliding downslope following the occurrence of the landslide diverted the river bed in the opposite direction. Most of the villages established on both banks along the valley of Botan Cayi River are located on old landslide material, landslide debris and erosional surface. The water emerging from the toe and foot of the older landslide material has promoted the horticultural activities. In line with the increase in water saturation of the rock and soil beneath the reservoir after water holding in the dam, new landslides can be expected around the active landslide areas. Based on their relative ages, the landslides mapped were classified into 7 groups. The symbol 1 was used for the oldest landslide and similarly, 7 was used for the youngest one. The landslides with the numbers 1,2,3,4 and 5 are the inactive, fossil landslides. The landslides indicated with 6 and 7 are active landslides. The landslides also were grouped based on flowing-sliding types and flowing-sliding materials except for dating.