In a pioneering effort, researchers from the Indian Institute of Technology (IIT) Delhi have successfully developed the first-of-its-kind national landslide risk map. The lack of a comprehensive map has been a significant challenge, particularly in the aftermath of natural disasters. The map, which is set to be published in the February 2024 issue of the journal Catena, aims to revolutionize disaster preparedness and mitigation strategies across the country.
Unique Challenge: Landslides in India
Landslides pose a unique and deadly challenge in India, affecting localized areas and making them harder to track and study with traditional methods such as satellite imaging. Unlike floods, landslides occur in approximately 1-2% of the country, making data collection more challenging due to their limited scope. To address this, Dr. Manabendra Saharia, an assistant professor at IIT Delhi, and his graduate student Nirdesh Sharma embarked on an ambitious project to create a comprehensive national landslide susceptibility map.
Data Collection and Factors Considered
The researchers began by collecting data on known landslides in the country, amassing nearly 1.5 lakh (150,000) such events from sources including the Geological Survey of India (GSI) and other global repositories. The team also identified 16 landslide conditioning factors, including soil cover, tree density, proximity to roads, and slope steepness. These factors were crucial in assessing an area’s susceptibility to landslides.
GeoSadak, an online system containing data on the national road network in India, played a pivotal role in providing information beyond urban areas, where landslides are less likely to occur but often go unnoticed.
Ensemble Machine Learning Approach
With data points for known landslide events and information on landslide conditioning factors, the researchers opted for an ensemble machine learning approach. This involved using multiple machine learning models to analyze the data collectively, mitigating the impact of any single model’s limitations. The ensemble machine learning models were then used to make projections for areas lacking landslide data.
High-Resolution Landslide Susceptibility Map
The culmination of their efforts resulted in a high-resolution landslide susceptibility map, named the ‘Indian Landslide Susceptibility Map.’ Impressively, the map covers the entire country, providing susceptibility estimates at a resolution of 100 square meters. This extensive and detailed mapping, unprecedented in its scale, offers policymakers a valuable tool to assess vulnerability and implement targeted mitigation measures.
Revealing Known and Unknown Susceptible Regions
The map confirmed the susceptibility of well-known regions, including parts of the Himalayan foothills, the Assam-Meghalaya region, and the Western Ghats. Furthermore, it unveiled previously unknown high-risk areas, such as certain locations in the Eastern Ghats, north of Andhra Pradesh and Odisha. These findings underscore the map’s ability to identify vulnerable regions beyond those with historical landslide data.
Recognition and Future Initiatives
Experts, including Madhavan Rajeevan Nair, former Secretary of the Ministry of Earth Sciences, commended the research as an excellent contribution. The map is poised to assist policymakers, organizations like the Geological Survey of India, the Ministry of Mines, and the National Disaster Management Authority in implementing targeted mitigation strategies.
Dr. Saharia and his team are not stopping here; they aim to leverage the data from the map to develop a ‘Landslide Early Warning System’ for India. Additionally, efforts are underway to create an infrastructure vulnerability map, highlighting roads, railways, and buildings particularly at risk of landslides.
The researchers have made the landslide susceptibility map publicly accessible through a web-based interface, allowing individuals to explore the data easily. This transparency aligns with their vision of empowering people with valuable information for better decision-making in areas prone to landslides.
As India grapples with the increasing impacts of climate change, this groundbreaking initiative by IIT Delhi stands as a testament to the power of technology in enhancing disaster resilience and preparedness.
Edited by Dr. Brijendra Kumar Mishra, (Disaster Risk Reduction Expert)