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Investigating the Fault Slip Behavior of an Extensional Faults System Through the Use of a Novel 3D Stochastic Declustering Algorithm: The Alto Tiberina Fault Case Study

Description: 

The Alto Tiberina Fault system is a seismic structure located in Central Italy, composed of a principal low-angle normal fault and other minor synthetic/antithetic higher-angle normal faults located in the hanging wall of the principal fault. In the last years, in this zone a dense seismic network has been deployed, making available a high-definition seismic catalog with a low magnitude of completeness. In this work, we applied a novel 3D stochastic declustering algorithm based on the ETAS model to such a catalog, in order to study the clustering properties of the seismicity by considering the earthquakes’ depth. We found two distinct behaviors for the seismicity in the principal fault and the synthetic/antithetic faults respectively, both in terms of clustering properties and magnitude frequency distribution. The principal fault shows a high b-value and low clustering (i.e. a majority of spontaneous events), while the synthetic/antithetic faults show a low b-value and high clustering (i.e. a majority of triggered events). Consequently, these results also imply a different b-value of the magnitude frequency distribution for spontaneous and triggered events, despite a similar rake of the focal mechanisms (normal faulting). Such a complex fault structure, therefore, shows peculiar and unusual seismic properties.

Session: New Methods and Models for More Informative Earthquake Forecasting [Poster]

Type: Poster

Date: 4/19/2023

Presentation Time: 08:00 AM (local time)

Presenting Author: Maura Murru

Student Presenter: No

Invited Presentation: 

Authors