Mapping Accelerated Displacement in a Himalayan Village
Joshimath, Indian state of Uttarakhand
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Differential ground movement in the town of Joshimath caused significant cracks in homes, schools, and hotels.
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The potential for further damage to infrastructure assets needed to be assessed to better inform local authorities.
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DInSAR analysis was carried out using historical and present data. Two years of InSAR data from the region were analysed to assess the magnitude and direction of displacement.
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This case demonstrates the ability of this retrospective methodology to be used in other cases to identify increasing movements and displacement triggering signs before they occur.
Highlights
Joshimath is a town in the Indian Himalayas popular with religious tourists due to its proximity to the Hindu holy site of Badrinath. Differential ground movement caused significant cracks in homes, schools, and hotels, displacing over 600 local residents.
The Challenge: Understanding Ground Displacement in Joshimath
Previous geomorphological studies relied on conventional methods that required extensive fieldwork and physical access across large areas. This approach was both time-consuming and challenging in the Himalayan terrain. Additionally, it was essential to determine the potential for further infrastructure damage and develop a clear understanding of the displacement trends. This information was critical to inform local authorities and guide efforts to stabilise the region.
The Solution: Utilising DInSAR Technology for Ground Monitoring
To accurately assess the ground movement in Joshimath, Differential Interferometric Synthetic Aperture Radar (DInSAR) analysis was employed. By using both historical and current satellite data, two years of ground displacement data from the region were analysed. This allowed experts to measure both the magnitude and direction of movement with millimetric precision.
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Geotechnical analysis further revealed that Joshimath’s foundations were inherently unstable. The town sits on a composition of sand and stone, which is highly susceptible to displacement due to vibrations caused by nearby blasting activities and heavy traffic. The analysis concluded that these factors contributed to a state of disequilibrium, worsening the ground instability.
Key Findings: Generating Displacement Maps
Through DInSAR analysis, displacement maps were created to visualise the extent of ground movement over time. These maps revealed critical insights into the patterns and trends of displacement in and around Joshimath. The detailed data provided local authorities with the information needed to prioritise interventions and focus remediation efforts on the most vulnerable areas.
The Benefits: Early Detection and Wide-Area Monitoring
The use of DInSAR technology offers several significant benefits for monitoring ground displacement:
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Wide-Area Coverage with a Single Analysis: DInSAR enables detailed data collection over large geographic areas, making it more efficient than traditional methods that require physical access and surveying.
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Retrospective Analysis: Historical data can be analysed alongside current data, providing a comprehensive view of displacement trends over time. This allows for early detection of ground movement and potential triggers before major events occur.
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Proactive Risk Management: By identifying areas experiencing significant displacement, stakeholders can take pre-emptive measures to address the underlying causes and prevent further damage to infrastructure and the surrounding environment.
Conclusion
The Joshimath case demonstrates the power of DInSAR technology in addressing complex ground displacement issues in challenging environments. The ability to gather high-precision data across large areas and analyse historical trends makes DInSAR an invaluable tool for proactive risk management. This retrospective methodology can be applied in other areas prone to displacement, helping authorities identify early signs of ground movement and mitigate risks before disaster strikes.
For more information on how DInSAR technology can enhance ground displacement monitoring for your projects, contact us today.