Nationwide Probabilistic Tsunami Hazard Assessment of Chile

Tsunami hazard along subduction-zone coastlines is governed not only by earthquake source characteristics but also by frequency-dependent interactions between tsunami waves and local bathymetric and geomorphological features, which can lead to resonance and wave amplification in specific coastal settings. Such effects can significantly modulate tsunami impact and are therefore essential to consider in hazard assessments. In this study, we conduct a fully probabilistic tsunami hazard assessment (PTHA) to quantify tsunami inundation along the Chilean coast using physics-based numerical simulations. The analysis incorporates seismic scenarios spanning a broad moment magnitude range (Mw 7.5–9.5) and applies multiple sampling strategies to evaluate the sensitivity of hazard estimates to the number of simulated events. The assessment is performed at a nationwide scale while considering tsunami inundation at several cities of interest, allowing comparing the effect of tsunami resonance across varying bays, embayments, and continental shelf structures. More than 40,000  stochastic earthquake–tsunami scenarios are simulated to characterize spatial variability in inundation metrics, including maximum flow depth, inundation extent, and temporal wave amplification, allowing to address uncertainties in both seismic sources and local amplification, as well as to test the convergence of typical PTHA statistics. These are compared with existing scenario-reduction strategies to assess their applicability and capability to preserve the statistical properties of the full catalogue. By linking PTHA with scenario reduction, it becomes feasible to both quantify hazard and explore effective risk-reduction strategies. These findings demonstrate that tsunami hazard is strongly region-dependent and controlled by both source variability and local resonance effects, providing critical input for risk-informed coastal planning, tsunami mitigation, and emergency management strategies in Chile. This work has been supported under the Geo-INQUIRE project, funded by the European Commission under project number 101058518 within the HORIZON-INFRA-2021-SERV-01 call.