Interseismic Deformation From Sentinel-1 Burst-Overlap Interferometry: Application to the Southern Dead Sea Fault

Interferometric Synthetic Aperture Radar (InSAR) data are increasingly being used to map interseismic deformation with ascending and descending-orbit observations allowing for resolving the near-east and vertical displacement components. The north component has, however, been difficult to retrieve due to the limited sensitivity of standard InSAR observations in that direction. Here, we address this problem by using time-series analysis of along-track interferometric observations in burst-overlap areas of the Terrain Observation with Progressive Scan imaging mode of the Sentinel-1 radar satellites. We apply this method to the southern part of the near-north striking Dead Sea transform fault to show that the similar to 5 mm/year relative motion is well recovered. Furthermore, the results indicate the locking depth of the fault decreases toward the south as it enters the transtensional Gulf of Aqaba basin. Our results show that time-series analysis of burst-overlap interferometric observations can be used to obtain meaningful interseismic deformation rates of slow-moving and northerly striking faults. Plain Language Summary Measurements of interseismic deformation near plate-boundary faults are used to estimate how large and how often major earthquakes are likely to occur and thus provide crucial input for regional seismic hazard assessments. Geodetic GPS data have primarily been used for this task, but increasingly Interferometric Synthetic Aperture Radar (InSAR) observations from satellites have provided useful information, particularly in areas where GPS observations are scarce. However, InSAR observations are only sensitive to the east and vertical components of deformation, but not to the north component, and are thus of limited use to study northerly striking earthquake faults. To address this problem, we combine an advanced processing technique called burst-overlap interferometry (BOI) with time-series analysis of a large data set to retrieve millimeter per year details of north-south deformation. We apply this method to the north-striking southern Dead Sea fault to show that the earthquake hazard decreases toward the south as the fault enters Gulf of Aqaba and approaches the Red Sea rift. Our study demonstrates that this method of BOI time-series analysis allows mapping the interseismic deformation of slow-moving and north-striking faults.

Automated summary

In this study, the researchers use a combination of advanced processing technique and time-series analysis to retrieve millimeter-level details of north-south deformation in areas where standard InSAR observations have limited sensitivity. The results show a decrease in earthquake hazard as the fault enters the Gulf of Aqaba basin. By applying this method, meaningful interseismic deformation rates of slow-moving and northerly striking faults can be obtained.