Fireball meteor creates seismic waves
Starry night with shooting stars (meteors). Image: Photo by Quentin Kemmel on Unsplash
A few weeks ago a sonic boom was captured by an NCRIS enabled seismometer at St Joseph's College in Albany, Western Australia. A few lucky locals even witnessed a spectactular light and sound show. The cause? A meteor exploding as it collided with the Earth’s atmosphere. Dr Michelle Salmon explains.
On 7 February, a seismometer at St Joseph's College, installed as part of the Australian Seismometers in Schools outreach project (AuSIS), captured the explosion of a fireball meteor that was observed streaking across the skies from Albany to Bunbury, but probably occured over the Stirling Ranges. Michelle explains:
“Unfortunately the WA skies were cloudy that night so the fireball in the sky was not picked up by cameras, but it boomed across our seismometer loud and clear showing that seismometers can be used for more than just detecting earthquakes!”
The signal received from the meteor at Albany. Image: Dr Michelle Salmon
A number of researchers at other locations around the country also tuned in to the signal. Jesse Dimech, from Geoscience Australia said a member of the public reported the event via the Earthquakes @ GA website:
“It is unusual for a member of the public to report a fireball in this way, so it must have been unusually loud or close. This is one of the clearest fireball signals I have ever seen on a seismometer."
The fireball also caught the attention of Curtin University. Through their analysis of the signal they were able to estimate that this meteorite must have been fairly large before it broke up, possibly weighing tens of kilograms. Alongside their general Earth Science program Curtin University has been engaging the public through their Fireballs in the Sky network, an award-winning citizen science initiative that connects the public with researchers and encourages individuals to report sightings.
Witnesses may have seen something like this meteor shower in 2018 that was caught on film in Perth.
At Australian National University, Geoff Bonning, a PhD student at studying meteorites, said:
"Most of the meteorites that hit the Earth come from the main asteroid belt, flung into the path of our orbit by Jupiter or Saturn. About 4,500 meteorites greater than 1 kg hit the Earth annually!"
This meteor struck at the peak of the Alpha Centaurides Meteor Shower and since, we have also been witness to the Lyrid Meteor Shower, just before Anzac Day. Indeed, celestial activity like this continues through time. Perhaps we can tune into the night sky and the global seismometer network in the COVID-19 pandemic, especially since we are experiencing a reduction in seismic noise due to reduced human activity.
AUTHORS
Philomena Manifold
and Dr Michelle Salmon
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For more information about this story, please contact Dr Michelle Salmon
Or, check out the IRIS Station Monitor for continuous, real-time ground motion from hundreds of locations around the globe that are generated by earthquakes, volcanic eruptions, and even meteorites!