Opinion divided on cause of landslide

While ecologists blame levelling work for the calamity, geological experts say this is exclusively a natural calamity.

Chandrakant Zanjare, who lost 13 family members in the landslide, wails near the site where his house stood at Malin village, Maharashtra, on Friday. Heavy rains hampered efforts by hundreds of rescue workers digging through heavy mud and debris, even as the landslide toll crossed 50.

The landslide at Malin village, which is nestled in the Sahyadri mountain range of the Western Ghats, has set alarm bells ringing about the impact of deforestation in this ecologically sensitive zone. However, geological experts say there is a natural structural weakness in the basaltic rocks here and the landslide was not man-made. 

Ecologist Madhav Gadgil says this area falls within the crest line of the Western Ghats.  Several hills here are used for rice cultivation. “We have heard that there has been a large amount of levelling in this area not just for cultivation but also by JCB machines to build roads. The latter is bound to have an impact,” Mr. Gadgil said.  

He said that excavation for large windmill projects in this region had also had a negative impact. “There has been a large amount of levelling work done for roads leading up to windmills in this area. The windmill lobby is politically well-connected. This has already triggered land-slides in this belt.”

However, others like research seismologist Arun Bapat dismissed the notion that the calamity could be man-made. “This is exclusively a natural calamity. It is not the result of any human activity,” he said.

Dr. Bapat said that the Malin disaster was a “rock-slide”. The Konkan region and Western Maharashtra are particularly prone to rock-slides. “Rocks develop fractures and cracks over time. When it rains hard and the velocity of the water flow is very high, the fractures in the rock could increase and trigger a rock-slide,” he explained.

Geologist Vivek Kale agreed that the region is naturally prone to rock-slides. “The basaltic rocks here are formed from horizontal lava flows. “They are horizontally stacked and there are zones of weakness in the interflow area. These zones are prone to slippage.”

The weak zones are naturally sealed by hard clay but continuous rain tends to make the clay slippery. “In such a situation, the area becomes prone to rock-slides,” Mr. Kale pointed out. He said that it is crucial to map out the hazard-prone zones and avoid settlements in their vicinity.