The technology to map landslides for India has previously been highly dependent on larger data sources; however, readiness for landslides can prevent a high level of human and ecology loss. India accounts for 8% of the global fatalities due to landslides, yet they are not considered as devastating as floods, storms, and droughts. In the recent devastating landslides in the Wayanad district of Kerala, while torrential rains are being considered the primary factors, tourism-driven real estate boom and unchecked construction are also contributors.
The state of Uttarakhand is also considered to be highly disaster-prone, with high occurrences of flash-floods, forest fires, and an increasing risk of landslides. In August 2023, heavy rainfall triggered landslides that killed more than 30 people in the states of Himachal Pradesh and Uttarakhand. Some reports also claim that there were reportedly 1000 landslide incidents in the state, causing the highest number of deaths in over eight years.
A newly developed susceptibility mapping technology that uses geospatial and ensemble machine learning found that the state of Uttarakhand and Sikkim are very highly susceptible to landslides; outside of the Himalayas, Kerala has been deemed to be the most vulnerable state, with over 14% of its land mass being in the “very high susceptibility” category. The same results have also been reflected by other national landslide susceptibility maps. The study made a distinction by using big data rather than coarse resolution data, which deals with larger volumes of structured, semi-structured, and unstructured data to give more accuracy to results. It found that a total of 13.17% of India is prone to landslides, and 4.75% falls in the highly susceptibility category. It has also reported that some areas in the Eastern Ghats around Orissa are susceptible, which has not been studied before.
According to reports, the 2023 Joshimath, Uttarakhand landslide that had resulted in approximately 700 buildings being damaged was caused by tectonic as well as human activities. Human activities have been known to trigger landslides by destabilising landforms, through activities such as poorly planned construction without proper slope grading, mining, and land development, among others. Back in 1976, the Mishra Committee warned about the risks associated with the Joshimath town, through findings that revealed that the town actually was built on sand and stone deposits from an ancient landslide, instead of a main rock. Despite decades of warning, the development of the town has seen construction of many hotels due to its closeness to religious pilgrimage sites. A similar plight has been shared by Wayanad in terms of the tourism related construction boom. Furthermore, in the case of Kerala, agricultural activities, such as monocropping, and plantation crops, such as tea and coffee which have replaced native trees, have led to a loosening of the top soil from the bedrock.
Understanding Communities Impacts
More than 380 people have been reported dead from the disaster in Wayanad, and many remain unidentified and missing. The government has launched rescue operations with the Army, Navy, K-9 Dog squad, NDRF and police officials conducting searches in six zones. Rehabilitation processes for families affected will likely begin soon, with nearly 4,833 people having been affected by the landslides in Mundakkai, Chooralmala, and Attamala.
In the aftermath of the 2019 landslides in Uttarakhand, the government took rehabilitation measures by relocating several families to Pipalkoti and other identified sites, such as Dhak and Gaunk Selang. But, for many, the loss of home comes at the cost of livelihood.
One community affected by the extreme weather conditions is the cattle-rearing nomadic tribe, Van Gujjars, who inhabit the foothills of the Himalayas in Uttarakhand, Himachal Pradesh, and Jammu & Kashmir. The migratory tribe has taken a severe hit to their livestock due to the weather conditions causing disruption in their migration routes, threatening the life of their cattle and causing damage to the pastures. The health of the animals has also affected milk production, which is a key source of income for the Van Gujjars.
On the other hand, Nainital is one of the most popular tourist destinations in Uttarakhand, and has been exposed to its own set of challenges. According to reports, the geological terrain around Nainital Lake has soft sedimentary rocks that make it more landslide prone. Since 2018, there have been visible changes in the terrain that have presented dangerous signs and disturbances, such as cracks alongside the Mall road of the Nainital Lake. The area has also witnessed landslides all throughout the month over the last couple of years. In mid-2023, landslides caused by seepage of rain and sewerage water posed immediate threats to the lives of some families living in the area. The government made relocation efforts for nearly 24 families, moving them to safer locations in the aftermath of the landslide.
Landslides have now been considered to be one of the biggest killers, close to 300 people have been killed due to landslides in the span of eight years between 2015 and 2023 in Uttarakhand, nearly 390 people in Kerala between 2019 and 2024, and many have been forced to migrate and rehabilitate.
Susceptibility Mapping
The government has made its own efforts to minimise the impacts of landslides by making plans to identify the areas where landslide occurrences are common or occur repeatedly. However, the commonly prevailing issue of unchecked construction has made the challenge more severe. In 2023, the government of Uttarakhand announced its intention to conduct a comprehensive survey of disaster-prone cities and towns, tenders for which had been invited. Similar steps have also been taken by other states, including Kerala, with the State Disaster Management Authority to map the threat of landslides and other occurrences; however, some of the data is over a decade old.
By employing new data driven susceptibility mapping technology, the government can further investigate the areas with higher susceptibility in the present scenario. Through identification of such areas, action plans for target risk reduction strategies, early warning systems, and strengthening land-use regulations can be prioritised. At the same time, the communities living in higher risk areas can have extended timely rehabilitation prospects. This proactive approach is essential as it not only helps avoid the loss of life, but also aids in strategic planning of development, in order to ensure safety and sustainability. Furthermore, susceptibility mapping supports effective resource allocation for emergency response and rehabilitation efforts, minimising the social and economic impact on the affected communities.
Although several attempts have been made through different models to evaluate and predict the occurrences of landslides, a promising mapping system with accurate results (current mapping accuracy reported to be 95.73%) could be a great technological advancement for the government, policy makers, and researchers alike. Other parts of the country, such as the Eastern Ghats, have also been reported to have increased susceptibility to landslides, which haven’t previously been studied by government reports. The reasons attributed to this increase in most parts, including the Himalayan states, are many, such as extreme rain, rising sea levels, more frequent wildfires, and thus, increased deforestation.
However, even with adequate mapping technology, some risks remain. Landslides can also be caused by human-induced changes of unchecked construction of roads, buildings, and dams, or other infrastructural projects. In the midst of the government’s push to ease pilgrimage passage through this delicate terrain, these risks remain unattended. In the midst of India’s myriad of challenges with climate, landslides have emerged as a big concern, causing risk to both life and property. Yet, the government’s response has been insufficient, partly because of the limitations to adequately predicting landslide occurrences. However, newly developing mapping technology with high accuracy can be used to streamline landslide management more efficiently.
