The Eltanin impact and its tsunami along the coast of South America: Insights for potential deposits

The Eltanin impact occurred 2.15 million years ago in the Bellinghausen Sea in the southern Pacific. While a crater was not formed, evidence was left behind at the impact site to prove the impact origin. Previous studies suggest that a large tsunami formed, and sedimentary successions along the coast of South America have been attributed to the Eltanin impact tsunami. They are characterized by large clasts, often several meters in diameter. Our state-of-the-art numerical modeling of the impact process and its coupling with non-linear wave simulations allows for quantifying the initial wave characteristic and the propagation of tsunami-like waves over large distances. We find that the tsunami attenuates quickly with η ( r ) ∝ r − 1.2 resulting in maximum wave heights similar to those observed during the 2004 Sumatra and 2011 Tohoku-oki tsunamis. We compute a transport competence of the coastal flow and conclude that for the northernmost alleged tsunami deposits, especially for those in Hornitos, Chile, the transport competence is about two orders of magnitude too small to generate the observed deposits.