# The 2022 Seismic Sequence in the Northern Adriatic Sea and Its Long-Term Simulation
## 1 Introduction  
In regions of moderate seismicity, the recurrence times of damaging earthquakes are commonly longer than the time windows covered by reliable historical observations, even in Italy, which owns one of the longest records of past strong seismic events. These limitations of historical seismic data preclude the application of statistical analysis for seismic hazard assessment, even if they can be partly overcome by geological and paleoseismological investigations on specific faults. The information on past earthquakes is particularly poor for offshore seismic activity (where paleoseismological and geomorphological studies are not feasible), as is the case for the thrust fault systems located seaside of the northern Marche coast (central Italy), recently affected by a seismic sequence that has significantly concerned the population in a large area of central Italy (Istituto Nazionale di Geofisica e Vulcanologia website at [[http://terremoti.ingv.it](http://terremoti.ingv.it)]([http://terremoti.ingv.it](http://terremoti.ingv.it)); main event of the sequence at [[http://terremoti.ingv.it/en/event/33301831](http://terremoti.ingv.it/en/event/33301831)]([http://terremoti.ingv.it/en/event/33301831](http://terremoti.ingv.it/en/event/33301831)), accessed on 14 February 2023; ISIDe_Working_Group [1], [PERSON] et al. [2]. The use of earthquake simulators has become increasingly popular in generating satellite earthquake catalogues with a vast number, even reaching millions, of events. This allows for statistical analyses to be conducted on simulated catalogues that are considerably more reliable than those conducted on real catalogues. However, criticism has been expressed regarding the practicality of simulated catalogues. Certain seismologists have pointed out that the algorithms used in earthquake simulators are based on oversimplified physical models and contain arbitrary assumptions, which pose significant challenges forcreating a dependable representation of actual seismicity. Nevertheless, a wide consensus does exist on the potential of earthquake simulators to provide support for historical observations in the context of seismic hazard assessment, as long as a realistic physical model is available and the results are based on reliable source parameters. Some examples of research in this area include [PERSON] et al. [3], [PERSON] et al. [4], [PERSON] [5]. In the frame of the ongoing debate on the usefulness of earthquake simulators, some valuable insights have also been gathered through the application of earthquake simulators to the seismicity of Italy, Greece, California, and Japan ([PERSON] et al. [6; 7; 8; 9], [PERSON] et al. [10]). These insights have been gained by comparing the simulated catalogues with real catalogues from the respective regions, and the results have shown that the same algorithms can be applicable in different geographic regions and on different magnitude scales. In a recent study by [PERSON] et al. [6], a new earthquake simulation code was developed, which included an enhanced Coulomb stress transfer among rupturing fault elements and increased production of multiple main shocks, frequently observed in earthquake sources of different mechanisms in Italy. To better understand the clustering behaviour of these events, a specific algorithm was created to detect and list inter-correlated earthquake clusters based on certain empirical rules. The simulated catalogue produced by this code exhibits spatiotemporal features that imitate those frequently observed in reality. Using a stacking procedure, [PERSON] et al. [6] were able to represent the number of moderate-magnitude events that preceded and followed stronger earthquakes in a 100,000-year simulated catalogue. Their results for the central-northern Apennines region showed interesting long-term acceleration and quiescence patterns of seismic activity before and after mainshocks.