Asteroids Are Bad at Making Waves
http://www.space.com/36451-asteroids-bad-at-making-waves.html
When an asteroid hits the middle of the ocean in Hollywood movies, it creates devastating waves that wipe out coastal cities. But new simulations reveal that
real asteroids don't make such a splash. That's because the crash releases most of its energy hurling water up into the atmosphere, and very little on making waves.
"The folklore has been that tsunamis from impactors will be the danger," Galen Gisler, who studies the physics of geological processes at Los Alamos National Laboratory,
said at the Lunar and Planetary Sciences Conference last month in The Woodlands, Texas. (Gisler also presented the work at the American Geophysical Union's fall meeting
in December 2016.) He ran 3D simulations that modeled wave formation from falling rocks of various sizes, as shown in this video, and found that the waves formed by
smaller asteroids resemble landslide tsunamis on Earth.
"The splash wave can be very dangerous — out to tens of kilometers — but beyond that, they fall away more sharply," he said.
Visualization and Analysis of Threats from Asteroid Ocean Impacts
https://www.youtube.com/watch?v=yeXcgnj8AG0