Infrasound: A particular form of damage from meteor hits

Posted on February 18, 2013  /  0 Comments

What we noticed in the aftermath of the 2004 Indian Ocean tsunami was the randomness of the damage. Houses that were right next to each other were affected differently: one destroyed another untouched. This was supposed to be caused by the complex interaction of the wave and the topography of the coast. In the case of the meteor hit that affected the Siberian city of Chelyabinsk, the damage has also been random according to reports. Sometimes with glass containers within a home damaged while the windows were not.

Infrasound waves have not previously been studied in a cityscape, Richard P. Binzel, a professor of planetary science at the Massachusetts Institute of Technology and an author of a textbook on asteroids and meteorites, said in a telephone interview. But he noted that the apparent randomness of the damage was consistent with the way such waves function.

“A shock wave can be coming from a particular direction, and if you face that direction you are more susceptible,” Dr. Binzel said.

“One building might shadow another, or you may have a street that is optimally aligned to channel the wave, either in a fortunate or unfortunate way.”

Peter Brown, a professor of physics at the University of Western Ontario, wrote in an e-mail that an infrasound wave “is very efficient at traveling long distances,” and that “windows, structures or even glass jars susceptible to resonate at this frequency could be a factor to seemingly random damage at widely disparate locations.”

Dr. Brown studied a similar, though smaller, explosion of a meteor over the Pacific Ocean on Oct. 8, 2009, which also sent out low-frequency waves, though too remote to affect homes or industry.

Given the capabilities our scientists have to track asteroids and meteors, early warning is possible. That means risk reduction is also feasible. But there will be considerable challenges in contending with randomness.

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