Characteristics of oceanic impact‐induced large water waves—Re‐evaluation of the tsunami hazard

Abstract

available online at http://meteoritics.org Characteristics of oceanic impact-induced large water waves-Re-evaluation of the tsunami hazard Abstract-The potential hazard of a meteorite impact in the ocean is controversial with respect to the destructive power of generated large ocean waves (tsunamis). We used numerical modeling of hypervelocity impact to investigate the generation mechanism and the characteristics of the resulting waves up to a distance of 100-150 projectile radii. The wave signal is primarily controlled by the ratio between projectile diameter and water depth, and can be roughly classified into deep-water and shallow-water impacts. In the latter, the collapse of the crater rim results in a wave signal similar to solitary waves, which propagate and decay in agreement with shallow-water wave theory. The much more likely scenario for an asteroid impact on Earth is a relatively small body (much smaller than the water depth) striking the deep sea. In this case, the collapse of the transient crater results in a significantly different and much more complex wave signal that is characterized by strong nonlinear behavior. We found that such waves decay much more rapidly than previously assumed and cannot be treated as long waves. For this reason, the shallow-water theory is not applicable for the computation of wave propagation, and more complex models (full solution of the Boussinesq equations) are required.

Sedimentological analysis of resurge deposits at the Lockne and Tvären craters: Clues to flow dynamics

“…6d) followed by a final stage of "oscillating resurge." At craters with target water depths greatly exceeding the height of the rim of the crater forming in the seabed, this anti-resurge may cause an outwards propagating tsunami-wave (Wünnemann et al 2007). Here we deal with the resurge deposits within and in direct proximity of the crater in the seabed, and not with distal tsunami deposits.…”

Hybrid modeling of the mega‐tsunami runup in Lituya Bay after half a century

“…[12] iSALE is validated against experimental studies of hypervelocity impacts and other hydrocodes [Pierazzo et al, 2008] and used successfully in modeling of meteorite impact wave generation studies [Weiss et al, 2006;Wünnemann et al, 2007].…”

Environmental Effects of Impact Events

“…Wünnemann et al (2007) showed that, in oceanic impacts, rim waves are the predominant waves in shallow-water impacts but decay rapidly in deep-ocean impacts. Collapse waves, on the other hand, are not a factor in shallow-water impacts, where the crater rim tends to stop water from flowing back into the crater and be affected by crater collapse, but they become the dominant waves in deepocean impacts.…”

“…The presence of sub-micrometre dust at the top of the atmosphere may reflect downward some of the IR radiated upward (Goldin and Melosh, 2009), and increase ground radiation. On the other hand, numerical simulations by Artemieva and Morgan (2009) indicate that a significant fraction of the K-Pg critical parameter is d/H, the ratio of impactor diameter d and ocean depth H. Wünnemann et al (2007) found that the smaller the d/H is the more rapidly the wave amplitude is attenuated with distance. For d/H < 0.4, rim waves are quickly dissipated and the main impact-generated wave is a collapse wave.…”

“…The consequences of a tsunami reaching coastal regions depends on local conditions, such as distance of the coastline from impact, ocean bathymetry and shore and coastal configuration (offshore slopes), and cannot be addressed easily in a general context Lynett, 2005, 2007;Wünnemann et al, 2007). Overall, a tsunami constitutes a short-term, mostly localized effect of an oceanic impact (at most the coastal regions delimiting the ocean basin), but it can have potentially devastating effects in highly populated coastal regions, thus creating a significant regional threat for human populations.…”