Along-Track Displacement of Mw 7.8 and 7.6 Kahramanmaraş Earthquakes from Sentinel-1 Offset Tracking and Burst Overlap Interferometry

Abstract

On 6th February, a pair of significant earthquakes with magnitudes of 7.8 and 7.6 struck Kahramanmaraş, Turkey. The Earthquake InSAR Data Provider (EIDP) promptly produced interferograms and offset tracking results within 3 hours of acquiring Sentinel-1 satellite data. However, it was challenging to unwrap the interferograms correctly due to high displacement gradient near the rupture. Hence, early displacement fields were derived from Pixel Offset Tracking (POT) method both in range and azimuth direction with low resolution depending on pixel sizes of Sentinel-1. We used the Burst Overlap Interferometry (BOI) method to extract the accurate along-track displacement and unwrapped the BOI interferogram using Azimuth Offset Tracking (AOT) data as a guide. Combining the unwrapped BOI interferogram and the AOT data, we derive a high-quality along-track displacement field that illuminates the entire earthquake rupture over 350 km and exhibits ±4 m displacement in the along-track direction.