Word: hagstrum
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...dinosaurs. But they are encouraged by a novel "double-whammy" theory suggesting that an impact on one side of the earth could produce massive volcanic activity at the antipode -- a point directly opposite on the far side -- and that the combined effect would cause disaster. Says Jon Hagstrum, the U.S. Geological Survey paleomagneticist who co-authored the theory: "This would be the best way to trigger worldwide mass extinctions because you have both hemispheres affected...
...Hagstrum's proposal is based on the tracking of seismic waves generated by earthquakes and explsions, which indicates that such waves emanating from a huge impact would be focused by the earth, converging on the antipode and releasing their energy there. This concentration of energy might heat and distort the crust, eventually creating plumes through which magma could burst to the surface...
...location antipodal to the Deccan Traps at the time of their formation is now on the floor of the eastern Pacific Ocean. Because the ocean floor moves like a conveyor belt, rising to form ridges and diving back into the earth in a process called subduction, Hagstrum says, "half of the ocean floor has since disappeared" and evidence of an antipodal impact "would be on that half...
...Hagstrum's proposal and some possible evidence of such double whammies on other planets and moons intrigued scientists at Sandia National Laboratories, in Albuquerque, New Mexico. Using a supercomputer, a Sandia team, headed by physicist Mark Boslough has been simulating impact effects, seeking to determine the size and velocity of an asteroid necessary to generate enough heat to cause volcanic outpourings at the antipode...
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