Co-seismic Ground Deformation Monitoring on Brebes-Segment of Baribis-Kendeng Fault Zone Based on Sentinel-1 Data

Abstract

Co-seismic deformation is a sudden change in the earth’s surface in a fault zone. Therefore, with modern satellite imagery, it is possible to investigate. Synthetic Aperture Radar (SAR) data from Mission Sentinel-1 is one example of satellite imagery that can be used to identify deformation. We employ the interferometry method by utilizing the Interferometric synthetic aperture radar Scientific Computing Environment (ISCE) and another InSAR software to monitor the co-seismic ground deformation in the form of line-of-sight (LOS) displacement. This research focused on the Brebes Segment of the Baribis-Kendeng Fault Zone and applied the interferometry method for the March 22, 2015, Balapulang earthquake (M4.7) and December 11, 2020, Brebes earthquake (M4.2). The earthquake event choice is based on the shallow depth of the hypocenter, which represents the earthquake originating from the fault in the crustal, not the megathrust subduction. The results show that despite the earthquake occurring under the thick quaternary sediment of the north shore of Java Island, the deformation caused by the co-seismic is still emerging to the surface. The LOS displacement was detected within the range of 6 cm from the ascending and descending track of the satellite sensors. Furthermore, this result may provide new information on the Baribis-Kendeng Fault zone, specifically the Brebes Segment.