The scientists, led by seismologist Kim Olsen of San Diego State University, produced for the first time realistic three-dimensional simulations of megathrust impacts on the Pacific Northwest region that includes the cities of Vancouver, British Columbia; Seattle; and Portland, Ore. Earthquakes with magnitudes greater than 8.0 on the Richter scale occur about every 400 to 500 years.

They discovered megaquakes can cause the ground to move 1.5 feet per second or more.

Olsen said the study implies the region could benefit from an early warning system that can allow time for protective actions before the brunt of the shaking starts.

Depending on how far the earthquake is from a city, he said early warning systems could give from a few seconds to a few tens of seconds to implement measures, such as automatically stopping trains and elevators.

"The information from these simulations can also play a role in research into the hazards posed by large tsunamis, which can originate from such megathrust earthquakes …"

The study is detailed in the Journal of Seismology.