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Centroid Moment Tensor catalog with 3D lithospheric wavespeed model: the 2016-2017 Central Apennines sequence
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  • Pietro Artale Harris,
  • Laura Scognamiglio,
  • Federica Magnoni,
  • Emanuele Casarotti,
  • Elisa Tinti
Pietro Artale Harris
Istituto Nazionale di Geofisica e Vulcanologia

Corresponding Author:[email protected]

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Laura Scognamiglio
Istituto Nazionale di Geofisica e Vulcanologia
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Federica Magnoni
Istituto Nazionale di Geofisica e Vulcanologia
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Emanuele Casarotti
Istituto Nazionale di Geofisica e Vulcanologia. Via di Vigna Murata
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Elisa Tinti
Università La Sapienza
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Abstract

Moment tensor inversions of broadband velocity data are usually managed by adopting Green’s functions for 1D layered seismic wavespeed models. This assumption can impact on source parameter estimates in regions with complex 3D heterogeneous structures and rock properties discontinuities. In this work, we present a new Centroid Moment Tensor (CMT) Catalog for the Amatrice–Visso–Norcia (AVN) seismic sequence based on a recently generated 3D wavespeed model for the Italian lithosphere. Forward synthetic seismograms and Fréchet derivatives for CMT–3D inversions of 159 earthquakes with Mw ≥ 3.0 are simulated using a spectral–element method (SEM) code. By comparing the retrieved solutions with those from Time Domain Moment Tensor (TDMT) catalog, obtained with a 1D wavespeed model calibrated for Central Apennines (Italy), we observe a remarkable degree of consistency in terms of source geometry, kinematics, and magnitude. Significant differences are found in centroid depths, which are more accurately estimated using the 3D model. Finally, we present a newly designed parameter, τ, to better quantify and compare a–posteriori the reliability of the obtained MT solutions. This parameter measures the goodness of fit between observed and synthetic seismograms accounting for differences in amplitude and arrival time, percentage of fitted seconds, together with the usual L2–norm estimate. These CMT–3D solutions represent the first Italian CMT catalog based on a full–waveform 3D wavespeed model and provide robust source parameters with potential implications for the structures activated during the sequence. The developed approach can be readily applied to more complex Italian regions where a 1D wavespeed model is underperforming.