Scientists at Idaho State University have mapped a new, active seismic fault in the Rocky Mountains in the US state of Idaho capable of unleashing a 7.5 magnitude earthquake.
A university official has warned the fault could release a damaging earthquake within the next few decades.
The 40-mile fracture runs close to the small town of Stanley, a community with roughly 100 year-round residents.
A 7.5 tremor is capable of devastating areas along a fault.
Researchers and scientists found the fault using remote sensing techniques that rely on laser-equipped planes.
They then analysed sediment cores taken from Redfish Lake in Idaho, which helped them uncover data about the history of the fracture in the Earth's crust.
Glenn Thackray, chairman of the university's geosciences department, said the fault at the base of the Sawtooth Mountains was of some concern, adding that if a quake did occur, shaking would extend to the state capital of Boise.
"There's a chance in the next few decades there will be an earthquake on this fault, and if it does happen, it will be a rather large earthquake," he told Reuters news agency.
Scientists believe two earthquakes have taken place along the fault in the past 10,000 years, with one occurring 7,000 years ago and the other 4,000 years ago.
This information has led researchers to believe significant seismic activity takes place in the region every several thousand years.
But John Ebel, a professor of geophysics at Boston College, says uncovering a fault of this magnitude should not necessarily serve as an "alarm that something is imminent".
The Northern Rocky Mountain region in Idaho, Wyoming and Western Montana is a seismically-heavy area capable of producing some very large earthquakes, Mr Ebel said.
"Since we don't know when the next earthquake will occur, we simply need to prepare for it," Mr Ebel told the BBC.
Mr Ebel said people in communities that lie along the newly discovered fault, like Stanley, should start educating themselves about quakes and begin earthquake drills in schools, if they are already not carrying out such procedures.
Emergency responders in the region should also have detailed plans on what to do if an earthquake occurs, and residents of the town should make sure any new structures in the area are brought up to modern earthquake codes, Mr Ebel said.