High quality comprehensive earthquake catalog of the Amatrice-Visso-Norcia seismic sequence (central Italy, Italian seismic Bulletin 2016-2018)

We present a high-quality catalogue of the Amatrice-Visso-Norcia (AVN) normal-faulting seismic sequence. We as analysts of the Italian Bulletin manually picked all the events with magnitude greater than 2.3 of the sequence, more over we performed a careful reprocessing of all the earthquakes (without any magnitude threshold) detected by the INGV real-time monitoring system in the first days after the Amatrice, Visso and Norcia mainshocks to create the first high-quality and comprehensive catalog of early aftershocks (Improta et al. Scientific Report 2019)

P- and S-wave first arrivals were hand-picked using all INGV stations installed in the epicentral region, 129 permanent and temporary INGV stations, station magnitudes were re-evaluated. Al the phase time arrivals and the amplitudes are now available in the ISIDe data base http://terremoti.ingv.it/en/iside.

We located more than 100000 aftershocks with a robust probabilistic, non-linear method achieving a significant improvement in the solution accuracy and magnitude completeness. The outcome is a high-quality catalog characterized by a significant improvement with respect to previous studies. Our catalog is of key importance for future seismological applications. For a prolific aftershock sequence like AVN, a high-quality initial catalog with a wide range of magnitude is a key ingredient for the successful application of detection techniques based on template waveforms cross-correlation and for optimizing automated picking algorithms and for high-precision double-difference relative locations. The new hypocenters provide a clearer image and improve our understanding of the activated fault systems. Future finite-fault inversions will benefit from geometric constraints on the activated fault systems and mainshock locations provided by this study. The new high-quality hypocentral locations will allow improving comparison between structures imaged by seismic reflection data and aftershocks distribution.