Publisher © Czech Geological Survey, ISSN: 2336-5757 (online), 0514-8057 (print)

Application of the Differential interferometry SAR and SBAS-DInSAR platform for surface deformations and vertical movements

 

Jan Jelének, Veronika Kopačková, Kateřina Fárová, Lucie Koucká

Geoscience Research Reports 50, 2017, pages 273–278

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Published online: 18 December 2017

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Abstract

Differential radar interferometry (DInSAR) was employed to identify post-volcanic and seizmic phenomena such as fault activation, volcanic uplift-subsidence effects and opening of ground cracks in central East African rift valley. In our study we focused on the investigation of seizmic activities connected with the earthquakes with estimated epicenter west of the lake Hawasa occurring on January 24 and 31, 2016 and following subsequent minor quakes during February 2016. Presented study tested freely accessible SBAS-DInSAR tool based on the G-POD platform (ESA), which was used for generating differential interferograms. SBAS-DInSAR tool uses ESA´s database of historical radar images from ERS and ENVISAT satellites as well as from a state-of-the-art Sentinel-1 satellite currently providing free C-band radar data. Sentinel-1 data, used for the interferogram generation, were chosen in order to measure changes before and after the earthquakes. Ascending track 160 and descending track 79 were identified as the most suitable. Coherence values, perpendicular baseline as well as temporal baseline were carefully assessed in order to obtain interferograms of the highest quality. Differential interferograms were compared with mapped faults, and as a result a new fault, which was activated by the earthquake, was detected using the time series of differential interferograms. In addition, temporal variations in the uplift-subsidence of the Corbetti volcano were analyzed in connection with the mentioned earthquake event. Subsidence, in comparison with a stable state before the earthquake, was observed in the period between March 22, 2016 April 15, 2016. Presented results showed that the differential interferometry and the freely accessible tool SBAS-DInSAR can bring new information that can’t be gathered by any other means with implications for structural geology as well as for seizmic- and volcanic-related analysis.