GNGTS 2022 - Atti del 40° Convegno Nazionale

GNGTS 2022 Sessione 2.1 221 THE RAPID ASSESSMENT OF SEISMIC MOMENT AND RADIATED ENERGY (RAMONES) SERVICE D. Spallarossa 1,2 , M. Picozzi 3 , D. Scafidi 1 , P. Morasca 2 , D. Bindi 4 , G. Tarchini 1 1 UNIGE, Genoa, Italy 2 INGV, Milan, Italy 3 University of Naples Federico II, Italy 4 GFZ, Potsdam, Germany Aim of this contribution is to introduce RAMONES (Rapid Assessment of MOmeNt and Energy Service), a service for disseminating through a web interface, the estimates of seismic moment (M 0 ) and radiated energy (E R ) for earthquakes occurring in central Italy with local magnitudes above 1.7 (Spallarossa et al. , 2021). The concept of RAMONES is to estimate M 0 and E R directly from features extracted directly from recordings, namely the S-wave peak displacement (PD S ) and the integral of the squared velocity (IV2 S ) evaluated over the S-wave window at local distances (Bindi et al. , 2020). In particular, RAMONES (http://www.distav . unige.it/rsni/ramones.php ) implements a fully-automatic procedure based on the following actions: (1) locations and magnitudes of earthquakes occurring within the target region are retrieved from the National Institute for Geophysics and Volcanology (INGV) bulletin; (2) hypocentral information are used to extract segments from continuous data streams archived in the ORFEUS-EIDA, the Incorporated Research Institutions for Seismology (IRIS), and the DPC repositories; a cut-off corresponding to hypocentral distances shorter than 150 km is applied to the waveform (and relevant station metadata) download; (3) an automatic procedure (Scafidi et al. , 2016) is applied to detect the P and S onsets, and to estimate the local magnitude; different features are extracted from the recordings, including the peak displacement (PD S ) and the integral of the squared velocity (IV2 S ) over the S-wave window, the peak ground velocity (PGV), and peak ground acceleration (PGA); (4) the seismic moment (M 0 ) and radiated energy (E R ) are estimated using empirical attenuation models as described in this contribution. Additional parameters, such as apparent stress (σ a ; Wyss and Brune, 1968) and the moment magnitude (Mw) are computed and disseminated as well; (5) the results are stored in a PostgresSQL database and disseminated through a web interface. A data set composed of 6515 earthquakes recorded in central Italy between 2008 and 2018 was used to calibrate the attenuation models relating M o to PD S and E R to IV2 S , including station corrections. The calibration values for M 0 and E R were extracted from the source spectra obtained by performing a decomposition of the Fourier amplitude spectra into source, propagation and site contributions, applying the so-called generalized inversion technique. To test the capabilities of RAMONES, we validate the attenuation models by performing residual analysis over about 60 earthquakes occurring in 2019 that were used for the spectral decomposition analysis but not considered in the calibration phase. A web portal allows the users to interact with the database. The main page of RAMONES (Fig. 1) includes: 1) A map of the monitored region showing the epicenters of earthquakes processed by RAMONES since January 2020. Using the “change selection” option, the geographical extension, the depth and magnitude ranges, and the time span of interest can be configured by the user. In its actual configuration, RAMONES analyzes earthquakes with magnitudes above ML 1.7 occurring in central Italy. 2) Selecting “seismic station,” RAMONES shows a table reporting the main information of the stations stored in the database and actually used by the service (more than 1500 considering both the whole Italian territory and adding selected stations from seismic networks operating in neighboring countries). In particular, the table includes the following: station information (code, network, channels, latitude, longitude, elevation, and location) including links; link to metadata (dataless); link to an automatically