Some thought it was a possum on the roof; one feared would-be burglars at the windows; others thought it was wind or thunder or noisy trains.
And at least one resident thought her cat had jumped off a cupboard in the next room.
What was all the fuss? It was an earthquake in Katoomba.
At 10.17pm on Wednesday, a 1.9 magnitude quake hit the Mountains, registering on the federal government website, earthquakes.ga.gov.au.
On the Blue Mountains Community Group Facebook page, residents in areas from Linden to Blackheath wrote of their experiences.
Anita Ramondetta posted: "I felt something in Lawson! Thought it was our heater starting up again."
Gemma Edwards in Linden said: "I thought the sound was one of the noisy trains and my pictures rattled on the wall. I live above the railway line."
Many of the reports came from Katoomba/North Katoomba/Leura but there were others from Wentworth Falls and Hazelbrook.
The tremor brought back memories of previous quakes. The last one in the Mountains was in October last year when a 2.4 magnitude hit between Katoomba and Jenolan Caves at 3.38 on a Saturday afternoon.
Many residents also remembered the massive Newcastle quake of 1989.
Amy Kate posted: "I was a little kid during Newcastle earthquake so didn't know what it was. I remember mum and dad talking about it. Mum said everyone ran out of the shops in Katoomba Street."
Rebbecca Ann Page recalled a tremor in the Mountains in the 1990s. "I swear it made some leaves fall off the trees outside."
Tongue-in-cheek, Sib Ben said: "Omg I knew this airport would cause these kind of issues!"
And, of course, at least one couldn't resist: Posted by Eugenia Irena Sakaluk: "Yes the earth moved for me too."
