In part one of the series, we highlighted how landslides, coupled with unplanned and rampant construction, have wreaked havoc on the town of Noklak in Eastern Nagaland.
The issue of landslides and Noklak sinking may have hit headlines now, but the state administration has been aware of the problem for one and a half decades. Locals say the Nagaland government started paying attention to the landslide issue back in 2008. This is confirmed by information made available under the Right to Information application filed by the Kiam Landslide Committee, which shows that the state government spent Rs 2 crore to improve urban drainage, construct check dams to control the debris, wire meshes to control the debris and implement afforestation of about 22 hectares of land in town. These efforts were undertaken from 2008 to 2010.
READ PART 1: Joshimath 2.0? Nagaland’s Noklak town is sinking; will the govt help?
However, the efforts did not yield any results.
In 2014, the entire southern and western slopes started sliding and completely damaged 60 houses.
“Several measures undertaken to stabilise the weak zones by afforestation, construction of check dams and wattles failed to control surface instability,” the Nagaland University geologists stated in their paper published in 2022.
Also Read | Joshimath 2.0? Nagaland’s Noklak town is sinking; will the govt help?
Kiam Landslide members are wary of the fixes and efforts undertaken by the state government to control it. “The money went into the drain, literally. The government did build the drainage lines, but the lines abruptly ended near the steep edges of the hills where land is sinking or being eroded by streams. During monsoons, there is water coming from everywhere. Wide cracks that appeared after the landslide turned into a drain so it could never be controlled,” H. Langshen, the General Secretary of the Kiam Landslide Committee explained to Eastmojo.
In 2018, the Nagaland State Disaster Management Authority (NSDMA) geologists identified a continuous cycle that may worsen the situation in future if not treated.
“The stream running down along the middle of the landslide has no proper drainage channel. During monsoon, as the water volume of the stream increases, the erosion on both sides of the flanks and along its bed occurs carrying down the debris to the Lien River. As fallen debris gets washed off, the upslope debris falls in again making it a continuous cycle all the year round,” the report stated.
Geologists from Nagaland University found tell-tale signs of mass wasting of land close to the drainage lines which aggravated the impact of the slow landslide and formation of cracks on the slopes. According to the geologists, the drainage, whether built or naturally formed, is experiencing gully erosion which often destabilises the slopes. “The frequency of landslides decreases further away from the drainage lines. The association of landslides with drainage is relatively high,” stated the paper.
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Drain hardly the ‘big’ problem
Fixing the drainage may not prevent the landslide in Noklak. Much like the hilly terrains of Northeastern India, the composition of several Nagaland hilly tracts is made of Disang shale, which is highly prone to landslides. Shale is essentially a fine-grained sedimentary rock composed of mud, which is a mixture of clay and silt-sized particles, organic matter and other minerals, especially Quartz and calcite.
“The study area consists mostly of crumbled, silty and weathered shale with subordinate amounts of shale with siltstone and soil debris. Of this, 45 per cent of the study area is made up of weathered shale, which has high landslide incidences of 71 per cent of the total landslide area. Though shale with siltstone occupies only 10 per cent of the study area, 15 per cent of the landslide incidences are observed here,” the Nagaland university study found.
Dr Temsulemba Walling, a professor of Geology at Nagaland University who was a part of the team that investigated the landslide, believes that the region is witnessing a spike in tectonic activity. During the study, Walling found a major lineament or geological fault crossing the town. These faults are formed mainly due to a collision between the Indian tectonic plate and the Eurasian plate about 90 million years ago, which eventually led to the rise of the Himalayas. Through the process of subduction, the Indian plate compressed under the Eurasian plate. Scientists have estimated that the Indian plate is currently moving northeastwards going under the Burma microplate at the rate of two centimetres.
“In such a scenario, new faults are formed or even older faults get activated leading to an increase in the tectonic activity,” Sarat Phukan, a Geology professor from Gauhati University who has been tracking neotectonic activity through his research, told EastMojo.
The Nagaland University paper has found that landslides occur closer to the lineaments or faults in Noklak town. “Tectonic activity has left its signature in many forms in the region. The subduction of the Indian plate beneath the Burma microplate has caused an NW-SE compression. Visual examination of satellite imagery shows a major NE-SW lineament crossing Noklak town. This trend is along the general thrust direction of the region. Lineaments play a dominant role in landslides,” the paper stated.
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‘Sitting ducks’
Even as residents are speculating that the town might be saved if they move away from south and west-facing slopes, the geologists have already found a new landslide in the eastern slopes as well.
“Another landslide located in the eastern portion of the town is also rapidly influencing instability in the area,” Walling and other geologists suggested.
Being in a highly-seismic zone, Noklak residents might have become sitting ducks in the larger geological upheaval that Northeastern India is witnessing. Unplanned urbanisation along with extreme weather events have heightened the susceptibility to landslides. One of the landslide committee members who attended an awareness and training workshop in Tuensang told EastMojo that NSDMA gave them earthquake preparedness training.
“However, there was no training for protecting each other from landslides,” the member said.
The only saving grace might be a team of geologists from the Geological Survey of India working in the area. According to a source in the district administration, GSI might dig deep boreholes on the Lien River to understand the depth of the landslide debris and the underlying faults crossing the town.
“Based on their assessment, we can suggest where the town could possibly move. We are not sure yet but something needs to be done,” the official told EastMojo.
For now, though, the locals can only hope and pray.
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