Study shows fallout of a giant meteorite strike on Earth


The Princeton model, which takes into account the Earth’s shape and surface features, shows that the meteoritic impact thought responsible for the mass extinction of the dinosaurs would have led to less severe seismic and volcanic activity than previously thought. (Image courtesy of Conor Myhrvold)

Seeking to better understand the level of death and destruction that would result from a large meteorite striking the Earth, Princeton researchers developed a new model that can not only more accurately simulate the seismic fallout of such an impact, but also help reveal new information about the surface and interior of planets based on past collisions.

The researchers created the first model to take into account Earth’s elliptical shape, surface features and ocean depths in simulations of how seismic waves generated by a meteorite collision would spread across and within the planet. Current projections rely on models of a featureless spherical world with nothing to disrupt the meteorite’s impact. The research was reported in the October 2011 issue of Geophysical Journal International.

The researchers — based in the laboratory of Jeroen Tromp, the Blair Professor of Geology in Princeton’s Department of Geosciences — simulated the meteorite strike that caused the Chicxulub crater in Mexico, an impact 2 million times more powerful than a hydrogen bomb and widely thought to have triggered the mass extinction of the dinosaurs 65 million years ago. The team’s rendering of the planet showed that the impact’s seismic waves would be scattered and unfocused, resulting in less severe ground displacement, tsunamis, and seismic and volcanic activity than previously theorized.

The simulations also could help researchers gain insight into the unseen surface and interior details of other planets and moons, the authors reported. The simulations can pinpoint the strength of the meteorite’s antipodal focus — the area of the globe opposite of the crater where the energy from the initial collision comes together like a second, smaller impact. The researchers found this point is determined by how the features and composition of the smitten orb direct and absorb the seismic waves. Scientists could identify the planet or moon’s characteristics by comparing a crater to the remnants of the antipodal point and calculating how the impact waves spread.

Lead author Matthias Meschede of the University of Munich developed the model at Princeton through the University’s Visiting Student Research Collaborators program with co-authors Conor Myhrvold, who earned his bachelor’s degree from Princeton in 2011, and Tromp, who also is director of Princeton’s Institute for Computa- tional Science and Engineering and a professor of applied and computational mathematics. The research was supported by the National Science Foundation and the German Academic Exchange Service.