William sent in a Yahoo link to a NOAA simulation of the tsunami waves generated by the dinosaur killing asteroid srike. You can watch the video on Yahoo but at the NOAA site you get a bit of text as well – see https://www.pmel.noaa.gov/news-story/first-global-tsunami-simulation-chicxulub-asteroid-impact-66-million-years-ago.html …. The asteroid, it says, was over 6 miles wide, and it triggered a megatsunami with mile high waves. New research shows it probably had a global impact. The new study is published in the journal AGU Advances and involved an international team of researchers. They used numerical analysis and three different models. They also reviewed geological evidence from one hundred plus sites worldwide and find evidence to suppport the models.
Basically, the tsunami was strong enough to disturb and erode sediments in ocean basins halfway around the earth – leaving either a gap in sedimentary records or a jumble of older sediments. The study, they say, is the first estimate of the global impact of the Chicxulub explosion. Models estimate that virually all world coastlines experienced catastrophic flooding, depending on the geometrics of the coasts and the size of incoming wave. Most coastal regions would have been inundated, and evolved to some extent. In some deep water basinsin the North Atlantic and the Pacific, for example, underwater currrent speeds exceeded 20 cm per second, and avelocity that is stronger enought to erode sediments on the sea floor. The energy of the tsunami wave was 30,000 times more powerful than the Boxing Day 2004 tsunami in the Indian Ocean, as a result of a deep earthquake.
Later, we are told, the researchers, at this stage, did not attempt to estimate the extent of coastal flooding caused by the tsunami. However, they have yet to find a connection between tsunami waves and the so called Interior Seaway of North America, or the laying down of chalk on the opposite side of the Atlantic.
At https://sos.noaa.gov/catalog/datasets/tsunami-asteroid-impact-66-million-years-ago/ … which describes how the simulation was made – and see also https://doi.org/10.1029/2021AV000627 … where we have the estimation the wave was perhaps 1 5 km high – but the initial wave might have reached 4.5 km in height [nearly 3 miles high]. The model also depicts the land masses as they were thought to have been 66 million years ago. That is perhaps an unknown.
The January 2022 Tonga submarine volcanic explosion demonstrated an additional mechanism for tsunami generation – the low frequency air pressure wave. This is known as the Lamb wave – and it is not fully understood, as yet. It is, however, clear that significant waves can be generated from such air pressure waves propagating over oceans. Analysis of this has not been done, for the most part. Based upon observation and moidelling of the Tonga volcano, it seems, that Lamb waves can generate signficant secondary tsunamis around the globe. These waves can generate significant secondary tsunamis around the globe. These waves would reach coastlines earlier than the tsunamis generated by the crater formation. They note the energy involved, of the Chicxulub impact, as at least 100,000 times large than the Tonga explosive volcano. This subject will be a feature subject of research.