Washington (AFP) - Americans living in the Rockies stand a better chance of dodging a zombie apocalypse than their urban counterparts.
Cities would fall quickly, suggests the "large-scale exact stochastic dynamical simulation of a zombie outbreak" from Cornell University in New York state.
But it would take weeks for a zombie plague to penetrate rural areas, and months to reach the Rocky Mountains, according to the highly mathematical study.
In pop culture, "if there is a zombie outbreak, it is usually assumed to affect all areas at the same time," said Alex Alemi, one of four graduate students in theoretical physics who undertook the research.
"But in our attempt to model zombies somewhat realistically, it doesn't seem like this is how it would actually go down," he said in a statement.
Based on the team's simulation, the densely populated and highly urbanized east and west coasts would be the first to succumb to a zombie plague.
Much of America would have fallen after four weeks, but it would take "a very long time" for zombies to reach the most remote corners of the nation.
"Even four months in, remote areas of Montana and Nevada (would) remain zombie free," the study says.
The study -- which mimics the way scientists forecast the spread of a real epidemic -- assumes an element of randomness in the way the zombie apocalypse would unfold within the Lower 48 states.
It also doesn't take into account a US military response: Last year it emerged that the Pentagon has a blueprint for combating the walking dead, which it uses as a training tool for its strategic planners.
The Centers for Disease Control meanwhile hosts a website called "Preparedness 101: Zombie Apocalypse" with practical advice on how to prepare for a zombie attack or any similar, more realistic catastrophe.
Wherever Americans might try to hide, however, the Cornell researchers concluded that, in the long term, when zombies attack, "We are largely doomed."
The study, titled "You Can Run, You Can Hide: The Epidemiology and Statistical Mechanics of Zombies," was presented Wednesday at a gathering of the American Physical Society in San Antonio, Texas.