Browsing by Author "Ruiz, Sergio"

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    33
    (33, 33) Fayaz, Jawad; Astroza, Rodrigo; Ruiz, Sergio; 33
    In the face of the unrelenting challenge posed by earthquakes—a natural hazard of unpredictable nature with a legacy of significant loss of life, destruction of infrastructure, and profound economic and social impacts—the scientific community has pursued advancements in earthquake early warning systems (EEWSs). These systems are vital for pre-emptive actions and decision-making that can save lives and safeguard critical infrastructure. This study proposes and validates a domain-informed deep learning-based EEWS called the hybrid earthquake early warning framework for estimating response spectra (HEWFERS), which represents a significant leap forward in the capabilities to predict ground shaking intensity in real-time, aligning with the United Nations’ disaster risk reduction goals. HEWFERS ingeniously integrates a domain-informed variational autoencoder for physics-based latent variable (LV) extraction, a feed-forward neural network for on-site prediction, and Gaussian process regression for spatial prediction. Adopting explainable artificial intelligence-based Shapley explanations further elucidates the predictive mechanisms, ensuring stakeholder-informed decisions. By conducting an extensive analysis of the proposed framework under a large database of approximately 14 000 recorded ground motions, this study offers insights into the potential of integrating machine learning with seismology to revolutionize earthquake preparedness and response, thus paving the way for a safer and more resilient future.
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    33
    (33, 33) Ortiz, Fabián; Pastén, César; Bustos, José; Ruiz, Sergio; Astroza, Rodrigo; Easton, Gabriel; 33
    Three-dimensional physics-based numerical simulations (3D-PBS) of the seismic response of the Santiago Basin, Chile, were performed considering a large-scale velocity model and shallow crustal earthquake scenarios, associated with the west-verging thrust San Ramón Fault. Numerical results show that competent gravelly soils in the center of the basin respond with low seismic amplification and shorter durations of strong ground motions, unlike less competent fine-grained soils in the northern area. A significant increase in the seismic intensities is observed in the vicinity of rock outcrops, attributable to the generation of surface waves. Seismic amplification factors were calculated with respect to a reference site on gravel and their values show high levels of amplification in the vicinity of the seismic source, and on soils with low shear wave velocities (Vs) and long fundamental vibration periods. On the other hand, empirical ground motion models (GMM) were used to estimate amplification factors for peak ground accelerations and spectral accelerations at various periods. Results from GMMs and 3D-PBS were compared, showing similarities in the attenuation pattern on stiff soils, but differences in soils with low Vs. Moreover, 3D-PBS captured site effects associated with the local geomorphology, unlike GMMs.
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    Two-dimensional simulation of the seismic response of the Santiago Basin, Chile
    Bustos, José; Pastén, César; Pavez, Diego; Acevedo, Miguel; Ruiz, Sergio; Astroza, Rodrigo