What radar technique compares radar images taken at different times to detect minute shifts in ground distance?
Answer
Interferometric SAR (InSAR).
The specific radar technique employed to measure ground displacement, which can be as small as a few millimeters over time due to seismic activity or human factors, is called Interferometric SAR, or InSAR. This method works by comparing two or more radar images captured over the exact same geographical area but taken at different points in time. By analyzing the phase differences in the radar signals reflected back from the ground across these time steps, scientists can calculate the precise shift in the distance between the satellite and the ground target. This capability is central to mapping deformation fields following earthquakes or monitoring gradual subsidence trends.
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