An active volcano in Ecuador could be on the brink of collapse.
New satellite data has revealed the west face of Tungurahua, which means 'Throat of Fire', is slowly deforming.
When the stratovolcano erupted in 1999, it forced the evacuation of 25,000 people, and has been active ever since.
Tech Times has described it as one of South America's most dangerous volcanoes.
If it collapses in the way geologists are predicting, it could lead to a massive landslide, causing widespread damage to the surrounding area.
Geophysicist James Hickey of the University of Exeter told MailOnline the instability they have detected could lead to a collapse in one day.
"The damage a collapse could have depends on how the volcano behaves and this is why it is important scientists continue to monitor it," he said.
However the scientists, who've had their research published in the journal Earth & Planetary Science Letters, don't know when it could happen.
Hickey told the outlet the west flank of the volcano is rapidly deforming, which means there are imbalances between magma being supplied, and magma being erupted.
"Shallow and rapid pressurisation from this inclined deformation source can generate shear stress along the collapse surface, which increases with greater volumes of magma," the authors wrote.
"This may contribute to slope instability during future unrest episodes and promote flank failure, with general application to other volcanoes worldwide displaying asymmetric deformation patterns."
If part of the volcano does collapse, it wouldn't be the first time.
There have been two documented collapses record - one about 12,000 years ago, then again 9000 years later.
That last eruption left a weak point on the mountain, which is where the latest collapse is located.
If another collapse occurs, it's likely the mountain will eventually rebuild itself, like it did in the past - but there would still be extensive damage to the surrounding area.