The district is prone to aborted landslips which pose a threat severe than the landslips that actually occur in the heavy rainfall.
An aborted landslip has signs similar to those of a landslip, though it may not occur at the same time of the rainfall. It poses a threat bigger than the actual landslip with weak layers causing slop failures, according to preliminary studies conducted by the Geological Department in Idukki.
The aborted landslip is due to the prevention of natural water flow either by human intervention or by natural factors, a senior scientist of the Geological Department told The Hindu on Tuesday.
A report on the rainfall pattern in the district and measures needed to rejuvenate the natural streams would be prepared soon, the scientist said.
It would help in taking timely measures to reduce the impact of landslip, he said.
Three spots identified
Though the department is yet to study the landslips on the Gap road stretch of the Kochi-Dhanushkodi national highway where a large number of landslips were reported, three areas have already been classified as aborted landslip areas in the district.
They are Vikas Nagar near Vandiperiyar and Memala in Peerumade and Muttukadu in Chinnakanal where the earth caved in.
In last year’s floods, 38 spots were identified for aborted landslips, which would raise the spectre of further landslips. The aborted landslips are the result of heavy rainfall. The natural flow of water is blocked, either naturally or by human intervention, resulting in water seeping into the earth. The soaked earth is much prone to landslips.
Larger area
The major landslips at Kavalappara in Malappuram and Puthumala in Wayanad have the features of aborted landslips. There would be more earth components than soil components in the debris and it will cover a larger area, according to the studies.
Soil sensitivity
The sensitivity of the soil could aggravate or reduce the impact of the landslips and the area-wise study of the soil condition is a pre-requisite for adopting landslip prevention measures in future.
The scientist said the natural water flow especially on the hills should be kept intact. Human encroachments blocking the streams cause aborted landslips leading to soil cracks and threat for major landslips.
Meanwhile, District Collector H. Dinesan has said that senior scientists of the Geological Survey of India would soon visit the district and those sheltered at the relief camps at the Kattappana town hall would be allowed to return to their houses.
