Impact of the Earthquake Rupture on Ground-Motion Variability of the 24 August 2016 M_w 6.2 Amatrice, Italy, Earthquake

Journal Article · Fri Jul 26 00:00:00 EDT 2024 · Bulletin of the Seismological Society of America

DOI:https://doi.org/10.1785/0120240002· OSTI ID:2532402

Akinci, Aybige ^[1]; Pitarka, Arben ^[2]; Harris, Pietro Artale ^[1]; De Gori, Pasquale ^[1]; Buttinelli, Mauro ^[1]

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1. Istituto Nazionale di Geofisica e Vulcanologia (INGV), Rome (Italy)
2. Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

Here, the devastating 24 August 2016 M_w 6.2 earthquake that struck Amatrice, Italy, marked the beginning of a prolonged seismic sequence dominated by three subsequent M_w ≥6.0 events in the central Apennines region. The earthquake destroyed Amatrice’s historic center, claiming the lives of 299 individuals and causing widespread damage in the neighboring villages. The severity of the ground shaking, with a recorded maximum acceleration of 850 cm/s² on the east–west component at the Amatrice station, was far greater than the predicted acceleration based on the Italian ground-motion model (GMM). As pointed out by several investigations, the observed ground-motion amplitude and its spatial variability during the earthquake can be linked to specific rupture characteristics, including slip distribution and rupture directivity effects revealed by the observed data (Tinti et al., 2016; Pischiutta et al., 2021). In this study, we conducted physics-based 3D numerical simulations of ground motion for the Amatrice earthquake for frequencies up to 3 Hz. We employed a series of kinematic rupture models and a well-constrained local 3D velocity model incorporating surface topography. The kinematic rupture realizations were generated using multiscale hybrid and fully stochastic models, following the technique proposed by Graves and Pitarka (2016). We focused on assessing the sensitivity of near-fault ground-motion amplitudes to earthquake rupture characteristics, in particular, the spatial slip pattern. To evaluate the quality of our simulations, we employed goodness-of-fit measurements performed in comparisons of simulated and recorded ground motions. The simulated ground motions compare well with the recorded data and predictions from GMMs for Italy, ITA18 (Lanzano et al., 2019). However, we found that the simulated interevent ground-motion variability (randomness in the source process) of peak ground velocity, σ (PGV) is higher than the constant σ (PGV) predicted by conventional GMMs. Our simulations using several rupture scenarios demonstrate that the near-fault ground-motion amplification pattern is directly related to the slip distribution pattern.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: AC52-07NA27344
• OSTI ID: 2532402
• Alternate ID(s): OSTI ID: 2571679
• Report Number(s): LLNL--JRNL-2002830
• Journal Information: Bulletin of the Seismological Society of America, Journal Name: Bulletin of the Seismological Society of America Journal Issue: 6 Vol. 114; ISSN 0037-1106
• Publisher: Seismological Society of America
• Country of Publication: United States
• Language: English

Related Subjects

3D Ground Motions Simulations
58 GEOSCIENCES
Amatrice Earthquake
Central Italy
Earthquake Rupture
Seismic Hazard
Topographic Effects