Listen to the Chelyabinsk fireball’s infrasound tsunami

 

Click image to see and hear multiple explosions of the fireball when it broke apart 12-15 miles high over Chelyabinsk, Russia on Feb. 15, 2013. This video scares me every time I see it.

You’ve probably seen and heard at least one video of February’s fireball exploding over Cheylabinsk, Russia. The shock wave from entry and subsequent break up of the meteoroid blew out thousands of windows, caused part of a building to collapse and set off countless car alarms.

A tiny sampling of the thousands of pea-sized meteorites recovered from the Chelyabinsk region after the fireball. Credit: Mike Farmer

Scientists estimate the incoming object measured about 55 feet (17m) across – as big as a 5-story building – weighed 7,000 tons and blazed across the sky at over 40,000 mph (64,000 kph). The shock pressure and heat upon entry converted much of the mass into dust, seen as a smoky “contrail”, and the rest into thousands of small meteorites that pocked snow drifts in the surrounding countryside.

Click image to listen to the atmospheric “tsunami” that sent waves of infrasound around the globe.

While the Chelyabinsk event was the most impressive witnessed meteor in more than 100 years, its effects were even more far-reaching. Almost 6,000 miles (9,600 km) away in Lilburn, Georgia a full 10 hours after the explosion, infrasound sensors recorded multiple rumbles from the object’s impact with the air.

Infrasound, a very low frequency sound wave that can travel long distances, can’t be heard by human ears but can be detected with sensors. When a large meteor enters the atmosphere it sends ripples of infrasound through the atmosphere and around the planet revealing information about its speed, direction of travel and how much energy it contains.

Locations of the Earthscope’s seismic sensors across the U.S. and into Canada. Click map and see if one is near you. Credit: National Science Foundation / Earthscope

Lilburn is home to one of nearly 400 seismic/infrasound stations in use in the eastern United States. They are part of a large-scale project named Earthscope, an initiative funded by the National Science Foundation that studies the Earth’s interior beneath North America. Although the stations mostly record seismic waves from earthquakes, they also are sensitive to long-period waves of infrasound.

Georgia Tech faculty member Zhigang Peng took the Lilburn infrasound data, sped it up and amplified it so we can heard the reverberations created by the falling meteoroid as it plowed through the atmosphere.

Click image to hear infrasound recording of a North Korean nuclear test and a magnitude 5.1 Nevada earthquake by Peng

“The sound started at about 10 hours after the explosion and lasted for another 10 hours in Georgia,” said Peng. Like a tsunami set in motion by an earthquake, the Chelyabinsk meteoroid created a series of tsunami-like waves in the atmosphere itself. Both travel at nearly the same speed.

Peng has used the same process to convert seismic waves and underground nuclear explosions into audible sound. Click above for a listen. Check out this site for more exploding Chelyabinsk videos.

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About astrobob

My name is Bob King and I work at the Duluth News Tribune in Duluth, Minn. as a photographer and photo editor. I'm also an amateur astronomer and have been keen on the sky since age 11. My modest credentials include membership in the American Association of Variable Star Observers (AAVSO) where I'm a regular contributor, International Meteorite Collectors Assn. and Arrowhead Astronomical Society. I also teach community education astronomy classes at our local planetarium.

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