Map of North America about 65 million years ago, showing the location of the Chicxulub crater in shallow waters of the Gulf of Mexico, and Tanis near the top of the Western Interior Seaway which then split much of what is now the continental USA. From here: https://commons.wikimedia.org/wiki/File:North_america_65mya.png

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   John Carlos Baez (johncarlosbaez@mathstodon.xyz)'s status on Thursday, 08-Aug-2024 04:24:14 JST John Carlos Baez

   Whoa. When that enormous magnitude-9 earthquake hit Japan in 2011, it caused waves 1.5 meters high in some lakes in NORWAY! That's surprising.

   And when that asteroid hit Chicxulub and killed off the dinosaurs, it caused an earthquake 4000 times more energetic. In a place called Tanis, now in North Dakota, this quake made waves 10 METERS HIGH! In the fossils there we see things like:

   • a turtle impaled on a tree branch
   • drowned ant nests with ants inside, filled with asteroid debris
   • fish found miles inland, with molten debris particles from the impact embedded in their gills as they tried to breathe.

   Back then, North America hadn't completely come together. The Western Interior Seaway went all the way up to Tanis. But the waves I'm talking about happened long before the enormous tsunami rolled up that seaway. That would have taken almost a day, long after the molten rock came down.

   All this is explained nicely here:

   https://en.wikipedia.org/wiki/Tanis_(fossil_site)

   and I thank @davidsuculum for telling me about it!