THIRUVANANTHAPURAM : Contrary to popular belief, studies indicate that rainfall is the primary factor triggering landslides, overshadowing human activities. The devastation in the scenic areas of Chooralmala and Mundakkai in Wayanad district has sparked a debate over the role of man-made factors in the disaster.
While environmentalists have raised concerns over deforestation and other human activities contributing to the calamity, geologists argue that the root cause remains natural even as human activities aggravate landslide conditions and increase casualties. Settlements in landslide-prone areas amplify the impact, geologists pointed out.
Sajinkumar K S, an expert on landslides and an assistant professor with the department of geology, University of Kerala, attributes landslides to natural factors. “Most landslides occur in forested areas with minimal human interference and are triggered by heavy, continuous rain,” Sajinkumar explained, based on extensive research across various regions in the country.
“The impact of human activities aggravates the situation, but if anthropogenic factors alone were the cause, we would see landslides occurring every season,” he said. Nonetheless, the role of human activities in increasing the death toll is clear, highlighting the need for effective mitigation plans. Despite having identified landslide-prone areas years ago, the state lacks a “run-out map” which would help anticipate the path of landslides.
“Residents may take comfort in occupying the lower susceptibility zones without understanding the unpredictable nature of debris flow movement. As such, it is essential to accurately predict debris flow run-out and the factor dominates many other factors that control the flow path,” Sajinkumar said.
A senior geologist, who wished to remain anonymous, pointed out that man-made factors exacerbate the situation, especially when construction permits are issued in hazardous zones. “When a river curves, people may view it as an ideal place to settle without recognising the underlying risks. The curve could be a fracture zone, and during a landslide, debris may not follow the curve but move straight instead,” said the geologist.