Asteroid Threat Assessment: Land versus Water Impact Risk

The Asteroid Threat Assessment Project (ATAP) team at NASA Ames Research Center has created a physics-based impact risk model to quantify the risk that asteroid impacts pose to Earth's population. The model uses Monte Carlo sampling to produce stochastic sets of potential impact scenarios based on uncertainty distributions characterizing key asteroid parameters. For each impact case, the entry and fragmentation process is modeled to compute the energy deposited in the atmosphere, determine airburst altitude or surface impact, and estimate the resulting damage areas and affected populations. Damage due to blast overpressure and thermal radiation is assessed for land impacts, and tsunami generation is assessed for impacts over the oceans. This presentation will describe the physics-based impact risk model, the generation of damage regions based on energy deposition profiles, and the adaptation of engineering tsunami inundation models for the current analysis. Modeling assumptions that have a strong impact on the integrated results will be discussed and compared to results from high-fidelity simulations. The overall probabilistic risks of water versus land impacts will be compared to quantify the relative hazard posed by each.