Tsunami Generation from Asteroid Airburst and Ocean Impact
Speaker: Darrel Robertson, Science & Technology Corporation (STC)
Presentation
Abstract
Simulation of asteroid induced tsunami waves from both airburst and ocean impact, using the ALE3D hydrocode, and their propagation. The goal of this work is to help determine the threat of asteroids entering Earth's atmosphere over the deep ocean, by examining the tsunami creation and possible shielding effects of the continental shelf. This seminar covers work presented in August at the NASA/NOAA workshop on asteroid generated tsunami. Previous work showed significant differences in expert opinions on the threat from asteroid induced tsunami. Earthquake induced tsunami have wavelengths on the order of 100 kilometers and can travel efficiently across ocean basins and create significant damage thousands of miles from the source. Conversely wind induced waves have wavelengths up to the order of 100 meters and are not a threat at significant distances from storms creating large waves. How big are asteroid induced tsunami and are they long wavelength waves that propagate efficiently or short wavelength waves that disperse quickly?
Biography
Darrel Robertson is an aerospace engineer in the Engineering Risk Assessment group at NASA Ames Research Center in California. He has 20 years of experience modeling complex fluid dynamic flows including combustion, and fluid-structure interaction such as blast loading and fragmentation. As part of the Asteroid Threat Assessment Project he has modelled the break-up and airburst of small asteroids such as the Chelyabinsk event, and tsunami generation from ocean impact. He earned his B.Sc. in Physics with Space Science from Leicester University in the UK, and his S.M. and Ph.D. in Aeronautics and Astronautics from the Massachusetts Institute of Technology.