Satellite Interferometry, InSAR

ECI utilizes an open source software package, GMTSAR, to process raw Synthetic Aperture Radar (SAR) images into interferometric SAR images (InSAR) which can be used to measure surface deformation related to earthquakes, landslides, mining and extraction of water, oil and gas. Multiple sets of InSAR images can also be stacked using an SBAS time-series processor to filter out the interference caused by moisture in the atmosphere and by ionospheric interference. This allows us to create models of surface deformation rates down to the order of millimeters per year. Multiple products can be created with the software in addition to the InSAR images. Images representing the coherence, or how well the two satellite images fit together is produced as a byproduct and can be used to map areas where the deformation is too great or too chaotic to be represented as an interferogram. This allows us to map surface ruptures of faults, landslides and liquefaction, covering large areas with one single set of radar images.

ECI staff is part of the development team behind GMTSAR, and as such has the ability to add or change features of the software in addition to correcting programming errors.

InSAR Products

Digital Elevation Models
Coherence Maps
Unwrapped Interferograms (Surface deformation models)
Stacked Interferograms

Case Study – 2019 Ridgecrest Earthquakes

The 2019 Ridgecrest earthquakes of July 4 and 5 occurred north and northeast of the town of Ridgecrest, California and west of Searles Valley, California (approximately 200 km [122 mi] north-northeast of Los Angeles). They included three main shocks of Mw magnitudes 6.4, 5.4, and 7.1,[4] and many perceptible aftershocks, mainly within the area of the Naval Air Weapons Station China Lake. In the weeks after the earthquake ECI staff produced an interferogram using GMTSAR software to process a single pair of Sentinel-1 SAR images acquired before and after the events on July 4 and 5. The coherence map shows the surface ruptures, landslides and liquefaction caused by the earthquakes and the interferograms show the location and magnitude of the surface deformation. Discover how the surface around Ridgecrest was impacted by the earthquake by scrolling through the image below.

Ridgecrest 2019 Earthquake


US National Map Imagery (1ft or better)

Ridgecrest 2019 Earthquake


SAR Correlation map

Ridgecrest 2019 Earthquake


Wrapped interferogram, 55.4 mm (2.18″) per color cycle

Ridgecrest 2019 Earthquake


Unwrapped interferogram Purple representing 120 cm (3.9 ft) of uplift, Red representing 120 cm (3.9 ft) of subsidence.