What Can We Do to Forecast Tsunami Hazards in the Near Field Given Large Epistemic Uncertainty in Rapid Seismic Source Inversions?

The variability in obtaining estimates of tsunami inundation and runup on a near-real-time tsunami hazard assessment setting is evaluated. To this end, 19 different source models of the Maule Earthquake were considered as if they represented the best available knowledge an early tsunami warning system could consider. Results show that large variability can be observed in both coseismic deformation and tsunami variables such as inundated area and maximum runup. This suggests that using single source model solutions might not be appropriate unless categorical thresholds are used. Nevertheless, the tsunami forecast obtained from aggregating all source models is in good agreement with observed quantities, suggesting that the development of seismic source inversion techniques in a Bayesian framework or generating stochastic finite fault models from a reference inversion solution could be a viable way of dealing with epistemic uncertainties in the framework of nearly-real-time tsunami hazard mapping. Plain Language Summary Owing to recent advancements in rapid seismic source characterization and tsunami simulation, nearly-real-time tsunami hazard forecasts in the framework of tsunami early warning systems are starting to be within reach. However, in this study we bring a note of caution regarding its future operational implementation since the level of uncertainty associated to a single rupture inversion is high and thus calls for the use of multiple realizations of seismic inversions to forecast inundation maps and assess their uncertainty bounds.