Vasily Vladimirovitch Titov

The Chicxulub crater is the site of an asteroid impact linked with the Cretaceous‐Paleogene (K‐Pg) mass extinction at ∼66 Ma. This asteroid struck in shallow water and caused a large tsunami. Here we present the first global simulation of the Chicxulub impact tsunami from initial contact of the projectile to global propagation. We use a hydrocode to model the displacement of water, sediment, and crust over the first 10 min, and a shallow‐water ocean model from that point onwards. The impact tsunami was up to 30,000 times more energetic than the 26 December 2004 Indian Ocean tsunami, one of the largest tsunamis in the modern record. Flow velocities exceeded 20 cm/s along shorelines worldwide, as well as in open‐ocean regions in the North Atlantic, equatorial South Atlantic, southern Pacific and the Central American Seaway, and therefore likely scoured the seafloor and disturbed sediments over 10,000 km from the impact origin. The distribution of erosion and hiatuses in the uppermost Cretaceous marine sediments are consistent with model results.

The 2004 Sumatra tsunami was an unprecedented global disaster measured throughout the world oceans. The present study focused on a region of the southeastern Pacific Ocean where the “westward” circumferentially propagating tsunami branch converged with the “eastward” branch, based on data from fortuitously placed Chilean DART 32401 and tide gauges along the coast of South America. By comparison of the tsunami and background spectra, we suppressed the influence of topography and reconstructed coastal “spectral ratios” that were in close agreement with a ratio at DART 32401 and spectral ratios in other oceans. Findings indicate that even remote tsunami records carry spectral source signatures (“birth‐marks”). The 2004 tsunami waves were found to occupy the broad frequency band of 0.25–10 cph with the prominent ratio peak at period of 40 min related to the southern fast‐slip source domain. This rupture “hot‐spot” of ∼350 km was responsible for the global impact of the 2004 tsunami. Data from DART 32401 provided validation of model results: the simulated maximum tsunami wave height of 2.25 cm was a conservative approximation to the measured height of 2.05 cm; the computed tsunami travel time of 25 h 35 min to DART 32401, although 20 min earlier than the actual travel time, provided a favorable result in comparison with 24 h 25 min estimated from classical kinematic theory. The numerical simulations consistently reproduced the wave height changes observed along the coast of South America, including local amplification of tsunami waves at the northern stations of Arica (72 cm) and Callao (67 cm).