GUWAHATI, June 29 – The landslides taking place in the city hills are mainly man-made. The soil of the city hills lack the binding capacity and due to the greed and ignorance of the land hungry people who are occupying the hills the natural slope of repose is not maintained making the slopes vulnerable.
This is the general opinion expressed by the geologists here, to this correspondent on the issue. They also called for a constant monitoring mechanism to check rampant unscientific slope cutting in the city hills.
Former senior geologist of the State Directorate of Geology and Mining Dilip Kumar Barman, who studied the phenomenon for more than 20 years, said that except the case of rock fall in Kalapahar area a few years back, all the cases of landslide taking place in the city are man-made.
The Kalapahar rock fall case was a natural one, resulting from scheroidal weathering and the subsequently triggered by the loss of the support-base of a round-shaped boulder under the impact of heavy precipitation, he maintained.
Dr Bhagawat Pran Duarah of Gauhati University said high rate of precipitation leads to high water infiltration in the hill soil thereby increasing the pore pressure within the soil reducing the frictional force and finally leading to slope failure. As, he said, the angle of repose in the slopes is not maintained by the people.
Moon Chandra Deka, who is working with the State Government, is of the view that the cases of landslide taking place in the city hills are mainly due to wedge and circular failure.
He also maintained that in the city hills rockslides are in fact taking place, not landslide. For, landslide is the terminology used for describing slip of huge amount of land caused by slope failure.
In Guwahati, artificial slopes caused by anthropogenic activities are leading to the incidents of rock slides.