The Cascadia Subduction Zone located off the Pacific coast has long been identified as the biggest earthquake threat in Western Washington.
A new report gives insight into the impacts if it ruptures, causing a 9.0-magnitude earthquake that could shake the Seattle area for more than 6 minutes.
The fault line is 700 miles long from Vancouver Island to Northern California and is located 70 miles off the coast.
According to the Cascadia Region Earthquake Workgroup, a Cascadia quake could cause more than 10,000 deaths, more than 30,000 injuries and cause around $49 billion in damages in Washington State.
"We don't want this to happen," said Bill Steele, University of Washington seismologist. "This report was not meant to scare people. But we want the region to be prepared."
Steele says that while many older buildings have been retrofitted to withstand a quake, the region is largely unprepared for an earthquake of that magnitude.
While earthquakes can't be predicted, there is a 10-to-15 percent chance of the Cascadia fault slipping in the next 50 years. The last known quake it produced was in 1700.
"All of the damage can be mitigated or alleviated somewhat by having a good plan," said Steele. "It's locked and loaded."