DOI: 10.13127/cmtc/2018_2020
title: Full Moment Tensor Solutions for ML ≥ 3.5 Etna earthquakes from October 2018 to December-2020 (CMTC_2018_2020)
title: Catalogo......
title: CMTC_2018_2020

description: We computed the full seismic moment tensor of 14 earthquakes (3.5 <ML ≤ 4.8) that occurred in the Etna area in the period October 2018 to December 2020 and were recorded by the seismic broadband network managed by Osservatorio Etneo (INGV-OE). The focal solutions computed are here reported and compared with that obtained using the standard first arrival polarities method, based on the assumption of a double couple source type. The full seismic moment tensor computation allows for a complete definition of the earthquake source, through the inversion of the seismic waveforms. It permits the calculation of the Seismic Moment, the Double Couple component (DC) which allows identifying the nodal planes of the focal mechanism, and the non-DC components as Compensated Linear Vector Dipole (CLVD) and volumetric (ISO). In a volcanic environment, such as Etna, the computation of the non-DC components can provide useful information for a comprehensive study of the source, accounting also for the role of magma in the generation of earthquakes (e.g. Saraò et al., 2001; 2010; 2016).
description: Abbiamo calcolato il tensore del momento sismico completo di 14 terremoti (3,5 <ML ≤ 4,8) localizzati nell'area etnea nel periodo ottobre 2018-dicembre 2020 e registrati dalla rete sismica a larga banda gestita dall’Osservatorio Etneo (INGV-OE). Le soluzioni focali calcolate sono qui riportate e confrontate con quelle ottenute utilizzando il metodo standard delle polarità dei primi arrivi, basato sull'ipotesi di una sorgente doppia coppia. Il calcolo del tensore momento completo consente una definizione completa della sorgente del terremoto, attraverso l'inversione delle forme d'onda sismiche. Esso permette di calcolare il Momento Sismico, la componente di Doppia Coppia (DC) della sorgente che permette di identificare i piani nodali del meccanismo focale, e le componenti non DC come Dipolo Vettore Lineare Compensato (CLVD) e volumetrico (ISO). In un ambiente vulcanico, come quello etneo, il calcolo delle componenti non DC fornisce informazioni utili per lo studio della sorgente, tenendo conto anche del ruolo del magma nella generazione dei terremoti (es. Saraò et al., 2001; 2010; 2016).
description: The starting dataset of 1 D hypocentral locations, local magnitude, and the epicentral area is coming from the “Mt. Etna Revised and Concise Seismic Catalog from 1999 ETNA RCSC" (Alparone et al., 2020  https://doi.org/10.13127/ETNASC/ETNARCSC) which collects local earthquakes recorded by the Permanent and Mobile Seismic Network, managed by INGV-OE.  The fault mechanisms by first polarities are derived from the “Sicily and Southern Calabria focal mechanisms catalog” (Scarfì et al., 2013 http://sismoweb.ct.ingv.it/maps/eq_maps/focals/index.php) and have been computed using the standard FPFIT code (Reasenberg and Oppenheimer, 1985).
The full moment tensor solutions have been calculated using TDMT (Time Domain Moment Tensor) software by Dreger (2003) integrated with the Minson and Dreger (2008) code, to compute the isotropic component of the source. We used waveforms from broadband 3-component stations provided by the permanent seismic network managed by OE. The data were checked for a signal-to-noise ratio greater than 5, corrected for the instrument response and the horizontal components were rotated to the great circle path. 
Green’s functions are computed by using the frequency-wavenumber integration code (FKPROG) of Saikia (1994) for the homogeneous layered velocity and attenuation models of Alparone et al. (2012) and Martinez-Arevalo et al. (2005). The data and Green’s functions were filtered in the frequency band 0.01-0.05 Hz or 0.01-0.10 Hz depending on the value of ML.
description: The catalog consists of three main sections. In the first one, the most important starting parameters such as Date, Time, Latitude, Longitude, Depth, Local Magnitude (ML), and Epicentral Area of the earthquakes, derived from “Mt. Etna Revised and Concise Seismic Catalog from 1999 ETNA RCSC" (Alparone et al., 2020) are reported; The second section shows the focal mechanisms, extracted from the “Sicily and Southern Calabria focal mechanisms catalog” (Scarfì et al., 2013) calculated assuming a DC source type (Double Couple solutions). The third section of the catalog is devoted to the full moment tensor inversion results, obtained by applying Dreger, 2003 and Minson and Dreger, 2008 codes (reported as FULL TDMT code). In detail, the third part of the catalog lists, for each earthquake, the best focal solution and the associated moment tensor depth (MT depth), Moment Magnitude value (Mw), strike (STR1, STR2), dip (DIP1, DIP2), rake (RAK1, RAK2) of the two possible nodal planes (in degrees), Seismic Moment (M0), DC, CLVD, ISO percentage components, and Variance Reduction value