Views
5 years ago

Prognosis and mitigation strategy for major landslide-prone areas Varunavat Parvat landslide in Uttarkashi

Prognosis and mitigation strategy for major landslide-prone areas A case study of Varunavat Parvat landslide in Uttarkashi township of Uttarakhand (India)

coloured, medium to

coloured, medium to course grained locally pebbly to conglomeratic. Pujargaon Metavolcanics is the youngest basic flow in the area and occupies southwestern corner of the study area (Figure 2). This member comprises green amygdaloidal schist which amygdules of quartz and zeolite (Agarwal and Kumar, 1973). Structure Examination of satellite images and field investigations have revealed the existence of some major structural discontinuities (anticlinal and synclinal axes, faults and Prognosis and mitigation strategy 629 Figure 2. Geological map of Uttarkashi and surrounding area

DPM 17,5 630 Figure 3. Structural map of Varunavat Parvat and surrounding area of Uttarkashi township lineaments) in the area. Most conspicuous structural discontinuity observed in the area is anticlinal axis and fault along Bhagirathi river referred to as Baragadi anticline and fault by Agarwal and Kumar (1973) and Indravati Bhagirathi fault by NRSA (2004). In the area under investigation the NW-SE trend of this discontinuity is traced along Indravati river from Ladari village upto further SE of Boga village. It is at Uttarkashi that the trend of this anticlinal axis and fault changes from NW-SE to E-W and this E-W trend is noticed along Badethi, Chamkot and Matli area and thereafter it extends in northwest direction. Bhagirathi river between Uttarkashi and Matli and in the further west follows this discontinuity and the broad river valley of Bhagirathi and its meandering channel at Uttarkashi and downstream and severe bank erosion by Indravati River and its broad valley indicate strong tectonic control that Baragadi anticline and fault exhibits over the river courses of Bhagirathi and Indravati at Uttarkashi and surrounding area (Figure 3). Another geomorphic expression of this discontinuity is the sudden change in the upstream NE-SW trend of Bhagirathi river at Uttarkashi, as it flows NE-SW in the upstream of its confluence with Indravati river and in the immediate downstream of the confluence Bhagirathi river follows an E-W trend. Another E-W trending structural feature in the area is synclinal axis of Sangrali - Khand syncline (Figure 3) also referred to as Kot syncline by Agarwal and Kumar (1973). NE-SW trending Pata-Sangrali fault intersects the axis of Kot syncline in the west of Sangrali. The slow flowage around Sangrali and Pata villages and escarpment in that area can be attributed to this discontinuity. NW-SE trending Kharuwan-Badethi anticlinal axis and fault is another major structural discontinuity in the area and can be traced from NW of Kharuwan to the SE of Wasunga village and extends further SE of Badethi. The NW-SE disposition of Wasunga-Badethi Fan in this area and

Disaster management strategy for potential slide zones of Kumarkhera in Narendra Nagar township of Tehri Garhwal district, Uttarakhand, India