Seismic Sensors Triggered By Fireball’s Explosion Over Greenland
A fireball that exploded over Greenland shook the planet so much that it triggered seismic sensors to go off. The event occurred back on July 25, but it was the first ever meteor to shake the Earth so violently that it caused a seismic event.
At approximately 8:00 p.m. local time on that day, residents of the town of Qaanaaq on Greenland’s northwestern coast reported seeing a bright light in the sky and feeling the ground shake as a meteor combusted over the nearby Thule Air Base, according to Live Science. That phenomenal event was detected by more than just human observers though.
A fireball was detected over Greenland on July 25, 2018 by US Government sensors at an altitude of 43.3 km. The energy from the explosion is estimated to be 2.1 kilotons. pic.twitter.com/EePuk14Pqd
— Rocket Ron (@RonBaalke) July 31, 2018
According to unpublished research presented on December 12 at the annual conference of the American Geophysical Union (AGU), that fleeting event triggered a seismic reaction.
Seismographic equipment, which had been installed near Qaanaaq just a few months earlier to monitor how ground shaking affected the ice, also recorded the fiery meteor blast. The Qaanaaq fireball provided scientists with the first evidence of how an icy environment — and, possibly, a distant ice-covered world — could respond to a meteor impact.
The first sign of the meteor was a brilliant flash in the sky over Greenland; the meteor was at its brightest at an altitude of approximately 27 miles (43 kilometers) above the ground, and it was traveling at nearly 54,000 mph (87,000 km/h), according to the International Meteor Organization (IMO). –Live Science
Many who witnessed the meteor’s explosion over Greenland said it was like a bomb going off, and the seismic measurements agreed. With a calculated impact energy of 2.1 kilotons of TNT, this blast was the second-most-energetic fireball of the year, Live Science previously reported.
The recordings were captured by the seismic sensors and interpreted by two Danish Seismological Network broadband stations in Greenland: TULEG (Station Thule) and NEEM (Station Eemian). Seismic equipment picked up tremors from the impact location as far as 218 miles (350 km) away. The scientists were then able to identify the seismic event that matched the arc of the traveling ground waves and estimate the impact point of the fireball, the researchers reported at AGU. Scientists were then able to pinpoint the epicenter of the event near Humboldt glacier on the Greenland ice sheet.