Asteroid Impact Crater Sizes in Water

The impact of asteroids into water were simulated with a hydrocode to examine the effects of size, speed, water depth, air pressure, and other parameters on the resulting transient crater size, which will determine the size of the resulting impact tsunami. Laboratory experiments were conducted at the corresponding Froude number of these impacts.

Of particular concern are tsunami waves created by impacts from asteroids in the 200 m to 1 km diameter range because this size of asteroid will likely impact the Earth's surface instead of airburst, and are small enough that global climate effects will likely be minimal.

Hydrocode simulations predict tsunami waves an order of magnitude smaller than previous semi-analytical models. Using new experiments and simulations, scaling laws are improved to account for effects such as finite water depth, atmospheric pressure, and water vaporization energy. This approach matches the impact crater sizes across a wide range of impact conditions from laboratory experiments to kilometer-size asteroid impacts.