Complex seismicity features observed in a high-resolution seismicity catalog for the Gulf of Corinth, Greece

Recent advances in seismology through newer machine learning based tools, template matching and double difference relocation allow to build high quality earthquake catalogs from continuous waveforms. Here, we apply a workflow combining these approaches and reducing computational cost to the Corinth Gulf, Greece. This extensional rift is characterized by a prolific seismicity mainly occurring as swarms and driven by a complex interplay between tectonic loading, fluid diffusion and aseismic slip. This area also benefits from the long-standing and dense instrumentation of the Corinth Rift Laboratory (EPOS NFO). Focusing on the year 2017, the catalog contains more than 100k events, that illuminate three different active areas and sequences (mainshock-aftershock sequences and earthquake swarms). This high quality catalog allows us to identify and define seismogenic structures, but also to gain insights on the driving mechanisms of these seismic sequences (fluids, aseismic slip, etc.), how they evolve in time and relate to known geological and tectonic features. In particular, we focus on the migration of the swarm fronts and bursts within the swarms, by studying both fast and slow migration patterns. As both types of migration are related to fluid-induced aseismic slip, this allows us to refine our general understanding of the driving processes of swarms.