Urban Subsidence Mapping With Sentinel-1 InSAR

ISEF Category: Earth and Environmental Sciences

Subcategory: Geosciences  ·  Difficulty: Intermediate  ·  Setup: Home Setup  ·  Time: 1 to 2 Months

The Hook

A city can sink by millimeters a year, and no one notices until roads crack or pipes fail. Satellite radar can catch that motion before your eyes can. You can turn free space data into a map of land movement, then compare it with water use records. That gives you a real geoscience project with a real-world payoff.

What Is It?

Subsidence means the ground sinks. Uplift means it rises. InSAR, short for interferometric synthetic aperture radar, uses repeated satellite radar images to measure tiny changes in distance between the satellite and Earth’s surface. Think of it like checking whether a floor has shifted by comparing two photos taken from the same spot, except the “photos” come from radar in space.

Sentinel-1 is a pair of satellites that collect radar data for free. ASF HyP3 is a processing service that helps turn those radar images into land motion products. You can use it to estimate where a city is moving up or down over time. Then you can compare those patterns with groundwater withdrawal records from USGS NWIS, which tracks water-related data in the United States. If pumping pulls water out of underground layers, the soil can compact and the surface can sink.

Why This Is a Good Topic

This topic works well because you can test a clear idea, and the data already exist. You do not need a wet lab. You can ask whether land motion lines up with groundwater use, land type, or distance from pumping areas. The project connects satellites, geology, and water management, so it feels real and current. You can also build useful skills in remote sensing, mapping, and data analysis.

Research Questions

• How does vertical land motion change near areas with high groundwater withdrawal?
• What is the effect of seasonal groundwater pumping on the rate of subsidence?
• Does subsidence differ between urban neighborhoods built on different sediment types?
• To what extent do Sentinel-1 InSAR displacement trends match USGS NWIS withdrawal records?
• Which areas show the strongest uplift or subsidence over the study period?
• How does the distance from major pumping wells relate to the magnitude of land motion?

Basic Materials

• Computer with reliable internet access.
• Sentinel-1 scene access through ASF HyP3.
• USGS NWIS groundwater withdrawal or related water records.
• Spreadsheet software for cleaning and graphing data.
• GIS software such as QGIS for mapping displacement.
• Notebook for tracking dates, sites, and processing choices.

Advanced Materials

• Computer with enough storage for radar products and GIS layers.
• Sentinel-1 interferograms or displacement products from ASF HyP3.
• USGS NWIS groundwater, well, or withdrawal datasets.
• Land cover and geology layers from USGS or state geologic surveys.
• GPS-referenced city boundary, aquifer, or pumping well location data.
• Statistical software for correlation or regression analysis.
• Python or R for spatial analysis and plotting.
• QGIS or ArcGIS Pro for layered map analysis.

Software & Tools

• ASF HyP3: Processes Sentinel-1 data into InSAR products you can analyze for land motion.
• QGIS: Maps displacement, water data, and geology layers in one place.
• Google Earth Pro: Helps you compare motion patterns with roads, buildings, and surface features.
• Python: Lets you clean time series data and test relationships with groundwater records.
• R: Supports statistical tests and plots for comparing motion across sites.

Experiment Steps

1. Define one city or region and pick a clear time window for your analysis.
2. Choose the land motion variable you will measure, such as line-of-sight displacement or relative subsidence rate.
3. Select control areas that should show weaker motion, so you have a comparison.
4. Match satellite dates to groundwater records and plan how you will handle missing data.
5. Build a map and a time series that let you compare motion across locations and dates.
6. Decide which statistical test will answer your main question without overstating correlation as causation.

Common Pitfalls

• Using scenes with poor coherence, which makes the displacement map too noisy to interpret.
• Comparing satellite dates with groundwater records that do not cover the same time window, which weakens the analysis.
• Treating line-of-sight radar motion as pure vertical motion without checking viewing geometry, which can distort the result.
• Ignoring local geology, which can make two places with similar pumping look very different.
• Claiming groundwater withdrawal causes subsidence without testing other drivers such as construction, drought, or tectonics.

What Makes This Competitive

A strong version of this project does more than compare two maps. It separates signal from noise, explains why certain neighborhoods move differently, and tests a specific mechanism. You can make it stronger by using multiple control areas, a clear uncertainty analysis, and a careful spatial statistic instead of a simple eyeball match. The best projects also connect the geophysics to a local planning question, such as where infrastructure risk is highest.

Project Variations

• Compare subsidence patterns in two cities with different aquifer management policies.
• Test whether land motion changes more over clay-rich areas than sandy areas.
• Analyze how drought periods change the link between groundwater withdrawal and surface deformation.

Learn More

• USGS NWIS: Find groundwater, well, and water-use data through the U.S. Geological Survey database search tools.
• ASF DAAC HyP3 Documentation: Read the processing guides for Sentinel-1 InSAR products at the Alaska Satellite Facility website.
• NASA Earthdata: Search for Sentinel-1 background material, remote sensing guides, and related Earth observation data.
• QGIS Documentation: Learn the free GIS workflow for mapping, layering, and measuring spatial data.
• Remote Sensing of the Environment journal: Search for review articles on InSAR, subsidence, and groundwater-linked deformation through your school library or PubMed-style journal access portals.