Vermont Meteor's Violent Explosion Causes Earth Tremors Detected by NASA

The meteor that exploded over the state of Vermont on the evening of March 7 was detected by ground-based seismometers, NASA has said. The space rock violently broke apart in Earth's atmosphere around 33 miles high, causing a shockwave that could be measured and heard by instruments.

NASA revised its speed estimate on March 8 and said the meteor was traveling at around 42,000 miles per hour. This is more than 20 times faster than a rifle bullet, or 55 times faster than the speed of sound. The speed estimate was based on more than 100 eyewitness reports.

The space rock then hit the Earth's atmosphere, where air resistance caused pressure to build up ahead of the asteroid at the same time as a vacuum was formed behind it.

This pressure difference caused the meteor to violently explode with the force of around 440 pounds of TNT. Local reports say the force was felt by those on the ground, while a boom was also heard.

NASA said: "Such a pressure wave can also couple into the ground, causing minor 'tremors' that can be picked up by seismic instruments in the area."

In addition to eyewitness reports, NASA said it had detected the meteor's explosion using three infrasound stations positioned nearby, which helped it calculate the explosion force. These stations look for low frequency sound that can travel great distances, and have picked up meteor explosions before.

Combining the estimated speed and explosion force, NASA said the meteor was probably about six inches across and weighed 10 pounds. The agency also said it was likely the space rock was once part of a larger asteroid that it had split away from.

The department said on Facebook: "A nice little firework, courtesy of Mother Nature."

One eyewitness said in the comments: "I saw this at about 5:38pm in Hillsboro NH, travelling northeast before it burned up. Bright red and orange, bright white right before it broke into pieces and disappeared."

Another said: "I had just walked out my front door in Fairfax with my dogs at about 5:40 pm. Then what sounded like a huge explosion and it continued to rattle for at least 15-20 seconds. My little dog was terrified and my big dog continued to growl."

The meteor was also caught on a webcam based at Burlington International Airport, streaking across the evening sky for about two seconds.

NASA attempts to capture meteors burning up in the sky using its All Sky Fireball Network—a collection of 17 specialized wide-view cameras based around the U.S. that are pointed towards the sky.

The space agency classes a burning meteor as a "fireball" if it becomes brighter than the planet Venus when it passes overhead.

On February 26, NASA's Fireball Network captured a bright fireball over Ontario which was seen by multiple cameras as well as observers in Michigan, New York, Ohio, and Pennsylvania. It was moving at around 65,800 miles per hour.

Meteor burning up
A stock image shows an artist's impression of a meteor burning up in Earth's upper atmosphere. NASA said the meteor blew up around 33 miles high. Solarseven/iStock