Numerical Seismic Hazard Assessment for the San Ramón Fault Using Heterogeneous Energy‑Based Kinematic Simulations

Abstract

Conventional earthquake simulations, employing computationally efficient but simplified homogeneous parameters, often yield unrealistic runaway ruptures and inaccurate ground motion predictions. Conversely, dynamic rupture simulations and large earthquakes reveal a strong correlation between accumulated energy and final rupture distribution, demonstrating that energy
constraints significantly reduce seismic source uncertainties. Therefore, realistic rupture analyses should prioritize energy constrained, heterogeneous models over probabilistic methods for seismic hazards analysis. This necessitates simulations incorporating fault heterogeneities and geometries, as demonstrated by the Heterogeneous Energy-Based kinematic method. This recent perspective
is particularly relevant for faults near urban areas such as the San Ramón fault which is located near the city of Santiago (Chile) and potentially impacting 6.5 million people. When considering ground motion amplifications, it is obtained a ground motion greater than expected for a magnitude 6.5 event, suggesting that the city could experience peak ground acceleration (PGA) values greater than 0.6 g at 10 km from the fault. The city would face maximum accelerations close to 0.9 g. PGA values close to critical structures, such as the ‘La Reina’ nuclear reactor, hospitals and the country’s government center, show accelerations higher than those recorded by the Fukushima-Daiichi reactor during the 2011 Tohoku earthquake.