Speaker: Marsha Berger (NYU / Courant)

Title:Modeling and Simulation of Asteroid-generated Tsunamis

Abstract: Four years ago, an asteroid with a 20 meter diameter exploded in the atmosphere over Chelyabinsk, 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 show simulations of tsunami propagation from asteroid-generated airbursts under a range of conditions. Our simulations use the open-source software package GeoClaw, which has been successful in modeling earthquake-generated tsunamis using 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 to explore the effects of wave dispersion and water compressibility. We end with a discussion of appropriate tools to study the more serious case of an asteroid that impacts the water.