Monitoring and inversion of three co-seismic events on the Balkan peninsula

The Balkan Peninsula is a tectonically active area due to the African-Eurasian collision, compression, and rotation of the Adria microplate in the north-west and rotation of the Anatolian plate in the south-east. The geographic region that comprises the Balkans is located in a very complex geological setting where many tectonic micro-plates meet and hundreds of faults cross the area. These processes generate frequent, though usually small, earthquakes, but occasionally earthquakes with magnitudes above 6.0 occur. In this study, SAR data from Sentinel-1A were utilized to analyze the deformation of co-seismic events. The Okada elastic dislocation model was employed to invert the geometric parameters of the fault and the distribution of co-seismic slip. The results indicate that the maximum uplift and the maximum subsidence deformations obtained from these two methods are comparable. The primary focus of the present study is to create a robust model of the surface displacements that occurred after three earthquakes: the Petrinja earthquake in Croatia on December 29, 2020, the Larissa earthquake on March 3, 2021, and the earthquake on Crete on September 27, 2021. A large earthquake releases sufficient energy to permanently deform the Earth`s crust and causes vibrations, affecting GNSS reference antennas. The examples presented demonstrate the application of space technologies such as GNSS and InSAR for researching and monitoring seismologic zones, highlighting their importance and advantages in establishing patterns in the movements within these zones.