Ground motion simulation of the 2021 Mw 5.2 Central Adriatic earthquake

In the last few decades, several series of earthquakes in the Central Adriatic Sea have been detected and analyzed, indicating the complexity of the tectonics within the Adriatic microplate. The most recent earthquake series suggests higher seismic potential than what was previously assumed and opens questions regarding present-day tectonic stress distribution within the Adria microplate in general. Therefore, studying seismic activity and identifying active faults is crucial when it comes to better understanding of the seismotectonics of this area, and consequently, improvement of the seismic hazard estimation. In this work we focus on the Mw 5.2 March 27, 2021 earthquake which occurred in the Central Adriatic Sea close to the island of Vis (Croatia). To evaluate the expected ground motion parameters of the event, we make use of physics-based waveform modelling. We simulate the earthquake using a newly defined 3D crustal model which honors surface topography, reflects main geological features and is embedded within the existing regional crustal model EPCrust. We compute broadband seismograms by making use of the hybrid approach where low-frequency and high-frequency parts are obtained separately and then combined into a single time series. We compare simulated waveforms against the recorded data and validate our results by assessing the goodness of fit for different ground-motion metrics. We then focus on simulating the waveforms using different descriptions of the source in order to investigate how its parametrization affects final results. This allows us to get a better understanding about the physical properties of the driving forces and mechanisms responsible for the seismicity in this region.