The AlpArray Research Seismicity-Catalogue
Authors: Bagagli M , Molinari I , Diehl T , Kissling E , Giardini D ,   AlpArray Working Group, Clinton John , Scarabello Luca , Käestli Philip , Racine Roman , Massin Frédérick , Pahor Jurij , Živčić Mladen , Plenefisch Thomas , Jia Yan , Csicsay Kristian , Ivančić Ines , Hetényi György , Abreu Rafael , Allegretti Ivo , Apoloner Maria-Theresia , Aubert Coralie , Besançon Simon , Bès de Berc Maxime , Brunel Didier , Capello Marco , Čarman Martina , Cavaliere Adriano , Chèze Jérôme , Chiarabba Claudio , Cougoulat Glenn , Cristiano Luigia , Czifra Tibor , D'Alema Ezio , Danesi Stefania , Daniel Romuald , Dannowski Anke , Dasović Iva , Deschamps Anne , Egdorf Sven , Fiket Tomislav , Fischer Kasper , Funke Sigward , Govoni Aladino , Gröschl Gidera , Heimers Stefan , Heit Ben , Herak Davorka , Huber Johann , Jarić Dejan , Jedlička Petr , Jund Hélène , Klingen Stefan , Klotz Bernhard , Kolínský Petr , Kotek Josef , Kühne Lothar , Kuk Krešo , Lange Dietrich , Loos Jürgen , Lovati Sara , Malengros Deny , Maron Christophe , Martin Xavier , Massa Marco , Mazzarini Francesco , Métral Laurent , Moretti Milena , Munzarová Helena , Nardi Anna , Pahor Jurij , Péquegnat Catherine , Petersen Florian , Piccinini Davide , Pondrelli Silvia , Prevolnik Snježan , Racine Roman , Régnier Marc , Reiss Miriam , Salimbeni Simone , Santulin Marco , Scherer Werner , Schippkus Sven , Schulte-Kortnack Detlef , Solarino Stefano , Spieker Kathrin , Stipčević Josip , Strollo Angelo , Süle Bálint , Szanyi Gyöngyvér , Szűcs Eszter , Thorwart Martin , Ueding Stefan , Vallocchia Massimiliano , Vecsey Luděk , Voigt René , Weidle Christian , Weyland Gauthier , Wiemer Stefan , Wolf Felix , Wolyniec David , Zieke Thomas 
Published: June 2022

Summary
We take advantage of the new large AlpArray Seismic Network (AASN) as part of the AlpArray research initiative (www.alparray.ethz.ch), to establish a consistent seismicity-catalogue for the greater Alpine region (GAR) for the time period 2016 January 1–2019 December 31. We use data from 1103 stations including the AASN backbone composed of 352 permanent and 276 (including 30 OBS) temporary broad-band stations (network code Z3). Although characterized by a moderate seismic hazard, the European Alps and surrounding regions have a higher seismic risk due to the higher concentration of values and people. For these reasons, the GAR seismicity is monitored and routinely reported in catalogues by a 11 national and 2 regional seismic observatories. The heterogeneity of these data set limits the possibility of extracting consistent information by simply merging to investigate the GAR's seismicity as a whole. The uniformly spaced and dense AASN provides, for the first time, a unique opportunity to calculate high-precision hypocentre locations and consistent magnitude estimation with uniformity and equal uncertainty across the GAR. We present a new, multistep, semi-automatic method to process ∼50 TB of seismic signals, combining three different software. We used the SeisComP3 for the initial earthquake detection, a newly developed Python library ADAPT for high-quality re-picking, and the well-established VELEST algorithm both for filtering and final location purposes. Moreover, we computed new local magnitudes based on the final high-precision hypocentre locations and re-evaluation of the amplitude observations. The final catalogue contains 3293 seismic events and is complete down to local magnitude 2.4 and regionally consistent with the magnitude 3+ of national catalogues for the same time period. Despite covering only 4 yr of seismicity, our catalogue evidences the main fault systems and orogens’ front in the region, that are documented as seismically active by the EPOS-EMSC manually revised regional bulletin for the same time period. Additionally, we jointly inverted for a new regional minimum 1-D P-wave velocity model for the GAR and station delays for both permanent station networks and temporary arrays. These results provide the base for a future re-evaluation of the past decades of seismicity, and for the future seismicity, eventually improving seismic-hazard studies in the region. Moreover, we provide a unique, consistent seismic data set fundamental to further investigate this complex and seismically active area. The catalogue, the minimum 1-D P-wave velocity model, and station delays associated are openly shared and distributed with a permanent DOI listed in the data availability section.