Marsha Berger
Courant Institute, NYU
"Modeling and Simulation of Asteroid-Generated Tsunamis"
Four years ago, an asteroid with a 20 meter diameter exploded in the atmosphere over Chelyabinsk, Russia, causing injury and damage 20 kilometers away but no deaths. We are studying the question of what would occur if such an airburst happened over the ocean. Would the blast wave generate a tsunami that could threaten coastal cities far away?
We begin with several simulations of tsunami propagation from asteroid-generated airbursts under a range of conditions. We use the open source software package GeoClaw, which has been successful in modeling earthquake-generated tsunamis. GeoClaw uses a basic model of ocean waves called the shallow water equations (SWE) We then present a simplified one dimensional model problem with an explicit solution in closed form to understand some of the unexpected results.
The SWE model however may not be accurate enough for airburst-generated tsunamis, which have shorter length and time scales than earthquake- generated waves. We extend our model problem to the linearized Euler equations of fluid mechanics to explore the e ffects of wave dispersion and water compressibility. We end with a discussion of suitable models for airburst-generated tsunamis, and speculate as to appropriate tools to study the more serious case of an asteroid that impacts the water.
Host: Kyle Mandli
