The meteor, which exploded above the city of Chelyabinsk in Russia on February 15, 2013, had injured over 1,000 people. New data now reveals that the atmospheric shockwave from that event circled the entire globe twice.
Ultra-low frequency acoustic waves from the explosion were recorded by devices meant to monitor nuclear explosions. The International Monitoring System (IMS) was originally designed to detect and record nuclear blasts in violation of the Comprehensive Nuclear Test Ban Treaty. The explosion created by the meteor was the most powerful shockwave, called infrasound, ever recorded by the system.
"For the first time since the establishment of the IMS infrasound network, multiple arrivals involving waves that traveled twice round the globe have been clearly identified. A preliminary estimate of the explosive energy using empirical period-yield scaling relations gives a value of 460 kilotons of TNT equivalent," Alexis Le Pichon, from the Atomic Energy Commission in France, said.
This means that the 50-foot-wide, 10,000-ton boulder from space created an explosion above the city of 1.13 million people that was 30 times more powerful than the atomic bomb that destroyed Hiroshima. Over 7,200 homes in six different Russian cities were damaged, when the meteor exploded after entering the atmosphere at more than 50 times the speed of sound. Atmospheric shockwaves from were recorded by 20 stations in the IMS system.
This encounter has now been ranked as the most powerful blast from space since 1908. That event, in the skies above Tunguska in Siberia, destroyed an estimated 80 million trees covering 830 square miles. That earlier explosion is estimated to have been in the range of 10-15 megatons of TNT, over 25 times as powerful as the most recent event.
On the same day as the explosion above Chelyabinsk in the Ural Mountains, a much-larger asteroid passed by the Earth. Those two nearly-simultaneous events raised awareness of the threat that our planet faces from incoming asteroids and comets.
In May 2013, a study appeared in the journal Planetary and Space Science which examined evidence collected from the site of the Tunguska explosion. The researchers were able to determine that the object that caused that event 105 years ago was likely a meteor rich in iron.
Study of the shockwave from the Chelyabinsk event appears in an advance online version of the journal Geophysical Research Letters, and will appear later in the same journal in its final form.
