Mystery surrounds numerous reports of a loud and unexplained "explosion" in the Lyneham area around 10.30pm on Thursday night, which startled people as far away as Kingston.
More than 12 hours later, police and emergency services are still none-the-wiser as to the source of the blast, which shocked the foundations of homes in Lyneham and sent reverberations through other northern suburbs.
An ACT Policing spokesman said officers responded to several reports of fireworks in the area around 10.30pm but could not locate anyone responsible or any fireworks material.
An ACT Emergency Services Agency spokesman said no requests for assistance had been made to firefighters or ambulance officers and the cause of the blast was unknown.
In the absence of an explanation, speculation has spread among Canberrans ranging from cannon fire, a head-on crash involving two trucks, an earthquake, or someone slamming a garage door with tremendous energy.
@SabraLane Could have been a minor earthquake, I remember one from about a decade ago, sounded like a garage door closing, but enormous— Nicholas Ellis (@electric589) August 14, 2014
@SabraLane Could have been a minor earthquake, I remember one from about a decade ago, sounded like a garage door closing, but enormous
Civic resident Amanda Kildea was still wondering what the cause of the explosion was on Friday afternoon.
“I live in Allara street in the city and the noise too got me out of my bed and out to the balcony at 11pm to see a puff of smoke rising from a few hundred metres down Constitution Avenue,” she said.
Another Civic resident, Jeff, also thought it came from the area.
"The explosion was in between the Carillon and Stage88 - north side of the lake (very close to the lake). Woke up when it went off and could see the smoke in the air from that area," he said.
"After the explosion, I saw a massive cloud of smoke in that location, and then heard motorbikes take off (red line their engines) from the area."
However, another Canberran thought the blast came from the Lyneham Netball Centre, although staff at the centre said they knew nothing about the mysterious blast.
@canberratimes Heard it coming out of Lyneham Netball Centre. It didn't sound like fireworks... And we all "felt" it. Actually pretty freaky— Sophie New (@sophie_new) August 14, 2014
@canberratimes Heard it coming out of Lyneham Netball Centre. It didn't sound like fireworks... And we all "felt" it. Actually pretty freaky
Mr White, a Lyneham resident, said he felt his floor move after the “very loud explosion” while Ms Ealing, who also lives in Lyneham, said she felt reverberations for a couple of seconds after the blast.
Some said the blast reminded them of the Mitchell explosions in 2011, which woke many North Canberra residents as a ferocious chemical fire swept through the Energy Services Environmental factory.
Remember the Mitchell chemical explosion in Canberra?— anita (@anitamaricic) August 14, 2014
Remember the Mitchell chemical explosion in Canberra?
Others questioned whether a military training exercise conducted at an Australian Defence Force range was the cause. Questions are in with Defence but we’re still awaiting confirmation.
@canberratimes yes in Lyneham, very loud like a cannon shot. It was about 10:30pm. Not sure what others were hearing at 11pm— David Kainer (@Kanizares) August 14, 2014
@canberratimes yes in Lyneham, very loud like a cannon shot. It was about 10:30pm. Not sure what others were hearing at 11pm
Did you hear the blast in Canberra on Thursday night? Leave a comment below the article and help Canberrans solve the mystery.