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Implication of Rupture Model Parameterization Uncertainty in Simulated Ground Motions From the Mw 6.2, 24 August 2016 Amatrice, Italy Earthquake

Description: 

The Amatrice, Italy earthquake occurred on 24 August 2016, with Mw6.2, and started a long seismic sequence dominated by three Mw≥6.0 events in the Central Apennines. It destroyed the historical center of Amatrice town, causing 299 fatalities, and induced spread damage in villages nearby as an effect of the causative fault's proximity and the high vulnerability of old buildings in the area. The ground shaking was severe and much larger than the expected value from the Italian ground motion model (GMM). Several authors have discussed the observed ground motion variability linked by the source rupture propagation and rupture directivity effects, as revealed by the observed data. In this study, we performed physics-based three-dimensional numerical ground motion simulations (up to 3 Hz) of the Amatrice earthquake using a series of rupture models and a well-constrained local 3D velocity model, including the surface topography in the near-source region. The kinematic rupture models are generated using the technique described by Graves and Pitarka (2016). We studied the sensitivity of near-fault ground motion amplitudes, particularly to the spatial slip pattern of the earthquake rupture model and its impact on observed and simulated ground motion amplification. We explored the ground motion variability and the uncertainty raised by the rupture model parameterization for the Amatrice earthquake. Finally, we compared the simulated ground motions with the recorded ground motions and those predicted by the GMMs, ITA18 (Lanzano et al., 2019), to investigate the performance of our simulations. We observed that our synthetic ground motions match well with the observed ones, reproducing the recorded ground motion characteristics in both the time and the considered frequency domains. The simulations' median ground motion intensities are similar to the ITA18 GMMs. However, besides a larger dissipation as a function of distance, our simulations predict higher ground motion amplitudes and higher standard deviations at short distances from the rupture, which can be attributed to fault rupture kinematics effects.

Session: Understanding and Modeling the Uncertainties in Earthquake Ground Motions [Poster]

Type: Poster

Date: 4/20/2023

Presentation Time: 08:00 AM (local time)

Presenting Author: Aybige Akinci

Student Presenter: No

Invited Presentation: 

Authors