Adelaide residents were rocked overnight by "extremely loud thunder" that shook windows and woke hundreds of people in the South Australian capital.
The disturbance was so great that the unusual meteorological event was initially thought to be a 1.4-magnitude earthquake.
Thankfully, no one was injured and no damage has been recorded. However, a video showing the force of the tremor was posted to social media.
South Australian Weather attributed the disturbance to "extremely loud thunder from the approaching storms".
"The first strike occurred at 2.06am just before the first rumbles were felt. I personally saw the second flash of lightning which was followed by the second window shaking rumble," it said.
It said on Friday night a warm layer air trapped cooler air below it trapping soundwaves from the "bass thunder low to the ground".
"So when thunder would normally be free to travel higher in the atmosphere this was condensed and trapped low to to the ground spreading out in a large area across the Adelaide area and Yorke Peninsula vibrating through houses/buildings giving the impression of an earthquake."
Bureau of Meteorology forecaster Matt Collopy told the ABC storms in the region meant loud sounds would travel long distances.
"I have had a bit of a look at the data from the lightning detection system and there certainly was lightning pushing across," he's quoted as saying.
"The other thing to note is, with this thick level of mid-layer cloud, so slightly higher cloud, the sound does travel quite substantially."Suggest a correction