6 OCTOBER, 2025
Newsletter
Urban Resilience & Smart Cities: InSAR for City-Scale
In this Newsletter we would like to talk about how cities can become more resilient by using advanced satellite monitoring technologies. Urban resilience depends on anticipating and managing risks such as subsidence, infrastructure settlement, and natural hazards. Interferometric Synthetic Aperture Radar (InSAR) provides millimeter-level accuracy over entire cities, enabling proactive management of urban systems. By looking at real case studies around the world, we can see how this technology is helping cities anticipate risks, plan for the future, and respond more effectively to disasters.
The challenges facing modern cities are unprecedented. Climate change, rapid urbanization, underground construction, and resource exploitation all put pressure on built environments. This raises critical questions: How stable are our foundations? Where are infrastructure risks emerging? And how can we prepare for sudden disasters? Traditional monitoring methods such as ground surveys and sensors provide high precision but only limited coverage. InSAR fills this gap by offering wide-area, repeatable, and cost-efficient deformation monitoring, independent of weather and daylight. Within smart city frameworks, where digital systems guide decision-making, InSAR is becoming an indispensable layer of information.
Planning for the future requires reliable data. InSAR allows city planners to identify subsidence zones caused by groundwater extraction, tunneling, or soil compaction, ensuring construction and land-use decisions are grounded in solid geospatial evidence. For infrastructure operators, InSAR goes beyond point-based monitoring by offering predictive maintenance for bridges, metro systems, highways, and railways. By detecting millimeter-level deformation trends, it supports early intervention and reduces costly failures.
In terms of resilience, InSAR also supports disaster risk management. Precursory deformation of slopes, dams, or urban structures can be tracked before catastrophic collapse, while post-event damage can be mapped quickly using radar coherence, even under cloud cover. These capabilities make InSAR an indispensable part of digital twins—urban simulations that combine sensor data, engineering models, and satellite observations into one decision-making tool. As cities grow under climate and population pressures, InSAR’s continuous, independent, and cost-efficient monitoring makes it a cornerstone of resilient, data-driven governance.
Several case studies highlight the value of this technology. In China, a large-scale study of the Shanghai– Nyalam highway corridor processed 446 Sentinel-1 images between 2018 and 2021, detecting 236 active landslides linked to rainfall and providing vital input for transport resilience. InSAR analysis of the 2016 Amatrice–Norcia (Italy) earthquake sequence revealed strongly asymmetric deformation. Vertical displacement peaked at nearly 100 cm of subsidence, compared to only 10 – 14 cm of uplift. This imbalance, with subsided volume about 7.5 times larger than uplifted volume, highlights the gravitational collapse of the hanging wall and demonstrates how InSAR captures critical features of normal fault earthquakes. In South Korea, monitoring of the Honam high-speed railway revealed subsidence rates of more than –12 mm/year in embankment zones. These findings, validated against ground-based surveys, confirmed InSAR’s role in predictive maintenance and sustainable urban mobility.
The impact of InSAR, however, goes beyond technology. Its true value comes from integration into governance frameworks. When embedded into municipal risk platforms, InSAR enables early-warning systems that provide real-time alerts for landslides, subsidence, or infrastructure stress—helping authorities act before disasters escalate. Continuous monitoring also supports regulatory compliance and environmental safety standards, particularly in areas affected by mining or construction. On a societal level, making InSAR- based deformation maps open to the public enhances transparency and accountability, allowing citizens to understand urban risks and the steps taken to address them. Finally, as many radar satellite missions operate globally, InSAR naturally benefits from international cooperation and cross-border data sharing, aligning with global sustainability goals while strengthening local resilience.
Resilient and smart cities require continuous, reliable, and scalable monitoring solutions. InSAR provides exactly that: a city-scale view of ground stability, infrastructure integrity, and disaster risk. The examples from Shanghai, Italy, and South Korea show how its value is already proven. The challenge now is institutional rather than technical—embedding InSAR into governance and planning so that every city can anticipate risks, adapt quickly, and thrive.
References
- Bignami, C. et al. (2019). Volume unbalance on the 2016 Amatrice-Norcia seismic sequence.
- Stephenson et al. (2021). Deep Learning for Damage Mapping with InSAR.
- Yi et al. (2023). Landslide Detection in Shanghai with InSAR.
- Lee et al. (2025). Railway Ground Deformation with PS-InSAR.
