Characterization of asteroid water impact crater and resulting sea surface response

Abstract:

To increase preparedness for low-probability, high-consequence events such as a Near Earth Object (NEO) hazard, numerical models are relied upon to establish emergency procedures and action protocols. Should a NEO such as an asteroid be on an Earth-impact trajectory, it is more likely to impact ocean rather than land. Therefore, numerical models capable of simulating water impact crater and resulting wave formation and propagation are necessary to assess the threat of a potential impact to critical infrastructure and to prevent loss of life.

Simulations of an idealized spherical asteroid impacting a water target are performed using ALE3D, a multi-physics hydrocode which uses an arbitrary Lagrangian-Eulerian advection scheme. Early time characterization of crater formation, shock propagation and atmospheric effects will be discussed, along with the transition of the impact energy to water vapor and wave energy, for a range of water depths. Furthermore, it is of interest to determine the likelihood of an impact event to create a tsunami wave, capable of traveling long distances without losing energy, and which present a threat to offshore structures and coastal communities. The long-term goal of this research is to couple the created wave energy with a wave propagation code appropriate to the regime of interest.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-813008