Ground Motion Variability and Near-fault Amplification: Insights From Modeling of the Central Italy Earthquake Sequences
Description:
This study explores ground motion variability to better understand the complexities introduced by earthquake rupture kinematics. Broadband simulations were conducted using hybrid deterministic and stochastic kinematic rupture models to analyze significant seismic events (M > 6.0) in central Italy, including the 2016 Amatrice Mw 6.2 and 2009 L'Aquila Mw 6.3 earthquakes. These events caused extensive damage and severe ground shaking, with recorded peak ground accelerations (PGAs) reaching 850 cm/s²—significantly exceeding predictions from the Italian Ground-Motion Model (GMM). Observed ground-motion variability has been linked to rupture characteristics such as directivity effects, as revealed by recorded data. Our simulations aimed to evaluate the impact of source rupture models on near-source ground motions and the role of topography in amplifying seismic waves in the most affected regions.
We utilized SW4, a 3D finite-difference code with a conforming curvilinear mesh, to model surface topography with high numerical accuracy. End-to-end simulations were validated against extensive recorded data and regional GMM predictions. Results demonstrated that near-fault amplification patterns strongly correlate with slip distribution, where large slip patches amplify ground motions and increase inter-event variability in Peak Ground Velocity (PGV), surpassing the constant variability assumed in GMMs. Our models successfully reproduced the amplitude and duration of observed near-fault motions, offering valuable insights into the factors influencing ground-motion variability during the earthquake sequences in central Italy. These findings advance the understanding of ground-motion complexities and their implications for seismic hazard assessment.
Session: Recent Advances in Modeling Near-source Ground Motions for Seismic Hazard Applications - I
Type: Oral
Date: 4/16/2025
Presentation Time: 08:30 AM (local time)
Presenting Author: Aybige
Student Presenter: No
Invited Presentation:
Poster Number:
Authors
Aybige Akinci Presenting Author Corresponding Author aybige.akinci@ingv.it National Institute of Geophysics and Volcanology |
Arben Pitarka pitarka1@llnl.gov Lawrence Livermore National Laboratory |
Pietro Artale Harris pietro.artale@ingv.it National Institute of Geophysics and Volcanology |
Pasquale De Gori pasquale.degori@ingv.it National Institute of Geophysics and Volcanology |
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Ground Motion Variability and Near-fault Amplification: Insights From Modeling of the Central Italy Earthquake Sequences
Category
Recent Advances in Modeling Near-source Ground Motions for Seismic Hazard Applications