InSAR can estimate surface deformation above a geological carbon storage site across a wide area and help assess whether observed changes are consistent with modeled subsurface processes. That makes it a valuable complementary evidence stream in a monitoring, measurement and verification (MMV) program, alongside pressure, seismic, geochemical and other site-specific measurements. It does not directly measure a CO₂ plume, prove caprock integrity or establish that there is no leakage, and understanding that boundary is key to using it well.
A surface signal is an indirect observation of the subsurface
Injection can change pressure and stress underground, but whether that produces a measurable surface response depends on depth, geology, injected volume, reservoir properties, geometry and competing background motion. A site can have substantial injection with little detectable deformation. On the other hand, observed uplift can reflect several processes that need investigating. You can read more about SkyGeo's research on InSAR detection for CCUS sites.
The absence of a significant InSAR signal therefore does not prove containment or show that the plume has not moved. The right question is whether a predicted surface response is large enough, and distinct enough from background variability, to be observed with confidence.
Test detectability before relying on InSAR for assurance
A practical pre-feasibility study combines geomechanical modeling with an assessment of historical radar observations and site noise. Predict the size and spatial pattern of deformation under plausible scenarios, then compare those predictions with the measurement uncertainty and with seasonal or regional trends. If the expected response is smaller than the background uncertainty, InSAR monitoring may offer only limited assurance for that mechanism.
SkyGeo's work with Stanford University addresses exactly this detectability question, bringing together modeling, long-term time series and background noise assessment. It shows a disciplined way to decide where InSAR can contribute. You can read more about SkyGeo's work on subsurface storage monitoring.
Align the evidence with regulatory requirements
Monitoring obligations vary by jurisdiction. In the United States, EPA Class VI requirements cover testing and monitoring of injection pressure and the carbon dioxide plume, among other responsibilities. These cannot be satisfied by claiming that surface uplift alone tracks the plume. Operators must develop a set of measurements and models that meets their regulator's expectations. You can find more technical detail in SkyGeo's scientific papers library.
InSAR can support comparison with predicted geomechanical behavior or provide independent surface observations over a wide area. Whether it suits a particular monitoring or assurance objective must be demonstrated for each site.
How should unexplained movement be investigated?
Start with measurement quality, reference stability, acquisition geometry and possible atmospheric or surface effects. Compare the timing and pattern with injection operations, well pressures, seismic surveys, groundwater changes and the current model, and update the interpretation as new information arrives. Do not turn an observed correspondence into an unsupported claim of plume migration or leakage.
The monitoring report should clearly separate measured ground motion, modeled explanations and unresolved uncertainties. This helps technical and regulatory reviewers understand what the evidence supports.
Is a flat InSAR time series good news for storage integrity?
It may show that no significant surface displacement was detected under the available observation conditions, but that is a narrower statement than proving integrity. SkyGeo can help assess whether InSAR adds useful, independently interpretable information to a site's wider MMV strategy.
Frequently asked questions
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Not on its own. A flat trend is useful evidence that no significant surface displacement was detected, but it does not establish seal integrity or rule out leakage, as deformation may be below the detection threshold or unrelated to containment.
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Not directly. Surface deformation is an indirect response shaped by subsurface conditions. Interpreting the plume requires geophysical, pressure and reservoir evidence.
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It can document observed surface movement, monitoring coverage, uncertainty, the period examined and how the information complements the approved storage monitoring program.
Assess InSAR detectability for a storage site
If you are developing an MMV plan, let's discuss whether modeled surface deformation could be resolved reliably at your site. Contact SkyGeo.
