When a magnitude-7.6 earthquake hit under the Banda Sea in the early hours of Tuesday, people hundreds of kilometres away woke up with a jolt.
A handful of houses in the Tanimbar Islands in Indonesia and two school buildings were damaged, with one person injured.
But in Australia, damage has been minimal, and the Bureau of Meteorology says there was no risk of a tsunami.
We asked Geoscience Australia's Senior Seismologist Trevor Allen about why this is, what exactly you should do in an earthquake, and other burning questions.
Hint, definitely don't stand in a doorway.
What causes an earthquake?
Essentially, the tectonic plates that cover the Earth are constantly bumping up against each other and become locked with one another. Over time, stress builds up on the edges of the plate boundaries.
When this stress becomes too great, the rocks will break, causing an earthquake.
"What we feel as the ground is shaking is actually the energy that's released when those rocks break, and that energy travels through the Earth," Trevor says.
"That's what we feel as the vibrations."
This earthquake in the Banda Sea was more than 100 kilometres deep. Authorities say deeper quakes cause less damage but are more widely felt.
What makes an area more prone to them?
Earthquakes can occur in pretty much any part of Australia at any given time. But, they're more frequent on the boundaries of these tectonic plates.
Mr Allen says the Banda Sea is one of the most "tectonically active areas in the world" because Australia's continental crust is butting up against the tectonic plate boundary, which is very rare.
"We do experience very large earthquakes at this tectonic plate boundary," he says.
"Since 1990, there have actually been around about 10, earthquakes of magnitude seven and greater. So that's roughly one every three years.
Do they occur in a pattern or at a certain time or year?
No, they're pretty much completely random.
And unlike other natural disasters, Mr Allen says their frequency is not impacted by climate change.
However, aftershocks are something to be wary of, with Geoscience Australia recording a 5.4-magnitude aftershock after this morning's earthquake.
Why were the vibrations so long and strong?
Despite being about 600 kilometres away from Australia, Mr Allen says for an earthquake of this size, the fastest seismic waves travel through the Earth at about seven kilometres per second.
"Because ... different components of the energy or the seismic shaking, travel at different speeds ... the further away you are from an earthquake, the longer the sensation the ground vibrations will actually feel," he says.
Also, as it turns out, Northern Australia's continental crust is really good at transmitting vibrations from earthquakes, making its residents more likely to feel them.
"This crust is very old, it's very cold and very dense," Mr Allen says.
"And that means that it actually transmits that quick ground shaking much more efficiently than, say, areas of younger crust or in a volcanic area."
Are some people more likely to feel them than others?
Yes, and the reason might surprise you. It turns out there's a certain frequency from an earthquake which moves really effectively through northern Australia's crust, and this frequency is quite sensitive to humans.
"It turns out that human jiggly bellies are really sensitive to that frequency, which is probably why so many people actually felt this event because it sets up a resonant frequency within our belly," Mr Allen says.
Why didn't we have a tsunami?
This earthquake hit about 90 kilometres under the Earth's surface, which means it was too deep to have much of an impact on the ocean floor.
But, tsunamis are certainly a possibility in Australia, with earthquakes in 2004 and 2006 resulting in tsunami waves reaching Australian shores.
What should you do if you experience an earthquake?
Mr Allen says standing in a doorway during an earthquake is a myth, and is actually a pretty bad idea.
"Doorways can can swing erratically in strong ground shaking, and you might end up with severed fingers or a broken nose," he says.
The best measure is to "drop, cover and hold". That means dropping to all fours, taking cover under a sturdy table or next to a wall, and holding on to the table leg or wall until the shaking stops, while covering your head with your free hand.
And also, don't run outside.
"We find that a lot of the injuries that occur in earthquake ground shaking is because people are trying to vacate buildings while the ground is unstable, so they might trip and fall," he says.
"Other times there could be non-structural components of a building like air conditioning ducts, or false ceilings or so forth, that actually fall in and injure people."
