The question of whether cities are sinking is critically important. Evidence from around the world shows that urban areas are sinking at alarming rates.
Land subsidence is when the ground slowly sinks. This can happen because of natural processes or human activities. One major cause is the over-extraction of groundwater. Population growth, urbanisation, and climate change exacerbate this phenomenon.
Real World Examples of Urban Subsidence
Mexico City
Over the last 60 years, Mexico City has sunk more than 32 feet because of extensive groundwater pumping. The city's geology, combined with its burgeoning population and water demands, makes this a pressing issue. Researchers warn that if this trend continues, critical infrastructure could face severe damage (The Independent).
United States East Coast
Cities like New York, Baltimore, and Norfolk are sinking at rates of up to 5mm per year. This subsidence compounds the effects of rising sea levels, putting roads, buildings, and essential services at risk.
High-resolution satellite data reveals important information. Over 2 million people live in areas at risk of subsidence. Additionally, these subsidence zones contain 800,000 properties. (The Independent).
Jakarta, Indonesia
Jakarta is one of the most extreme cases in the world. In some areas, it is sinking by up to 10 inches each year. The Indonesian government is even planning to relocate the capital to mitigate the risks (Virginia State News).
Why Does Subsidence Matter?
Subsidence is not just a geological curiosity; it is has tangible consequences. It can compromise infrastructure stability, leading to cracked foundations, buckled roads, and damaged water and gas lines. In coastal areas, it intensifies the risk of flooding by lowering the land relative to sea levels.
How Can Remote Sensing Help?
At Geofem, we use satellite remote sensing technology for infrastructure monitoring. One method is InSAR, which stands for Interferometric Synthetic Aperture Radar. This technique helps us monitor and map ground movement with millimetre precision. This technology uses satellite images to provide critical insights for infrastructure managers, helping them to:
Identify high-risk areas.
Plan maintenance and adaptation strategies.
Enhance resilience against subsidence-related challenges.
As cities grow and climate challenges intensify, understanding and mitigating land subsidence becomes ever more urgent. Tools like satellite remote sensing data empower decision-makers to act before subsidence becomes catastrophic. For urban centres globally, the question isn't just "Are cities sinking?" but rather, "What are we going to do about it"?
Would you like to learn more about subsidence susceptibility mapping? Contact Geofem today.
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