Oral Presentation

Understanding how ruptures initiate, propagate, and arrest is key to advancing physics-based ground motion simulations and improving seismic hazard assessment. In this presentation, I explore two complementary strategies that integrate observations and modeling to investigate rupture dynamics and high-frequency radiation.

The first approach focuses on natural earthquakes, where we use dynamic rupture modeling to assess the physical plausibility of kinematic source models inferred from seismic observations. Our aim is to reproduce observed low-frequency ground motion features (typically up to ~0.5–1 Hz) using families of physically consistent dynamic models. Previous studies, such as Tinti et al. (2021), have shown that this is possible for a range of rupture scenarios. Extending these models to higher frequencies remains a challenge. In the literature, this is often addressed by incorporating stochastic high-frequency components or by introducing heterogeneity into the source models. While promising, these strategies require careful physical and numerical constraints to ensure realistic energy radiation, consistent with what engineers would expect in real-world scenarios.
The second approach leverages high-resolution observations of induced microseismicity in underground natural laboratories. These environments provide access to rupture processes at small scales with exceptional detail. Here, we use theoretical dynamic models to predict how different rupture arrest mechanisms — such as gradual self-arrest or abrupt stop at barriers — influence high-frequency ground motion. Our simulations suggest that these mechanisms produce distinct spectral signatures, which may offer new physics-based diagnostics to interpret rupture processes from seismic records.

Together, these two perspectives — reproducing observed features of natural earthquakes and predicting observable features of induced events — underscore the importance of linking rupture physics to measurable ground motion characteristics across scales. Insights from laboratory-scale experiments, such as those conducted at the Bedretto Underground Laboratory — which aim to improve earthquake predictability, deepen our understanding of rupture physics and scaling laws, and advance safe geoenergy practices — may also inform future SCEC activities and statewide efforts.