(WSB Radio)  The earthquake that struck Haiti two weeks ago was the strongest in that country in more than 200 years.

The 7.0 magnitude quake devastated the capital city of Port au Prince and may have killed upwards of 200,000 people.

So, could a similar quake hit in the U.S?  It's possible and in places you might not imagine.

We all know about California and major earthquake faults near San Francisco and Los Angeles.  They've been waiting for "The Big One" since 1906, when San Francisco was nearly destroyed.

But other American cities, some not that far from Atlanta, are also in danger of a massive quake, and those cities are not that prepared in case one hits.

"Memphis is one fairly close to Atlanta," says Dr. Glenn Rix, professor of civil and environmental engineering at Georgia Tech.  "St. Louis, to a similar extent.

"The New Madrid Seismic Zone lies between St. Louis and Memphis, closer to Memphis," Rix says.

He tells WSB, while the New Madrid fault might not be as well known as the San Andreas fault, its potential for destruction is just as serious.

"Earthquakes in the central United States have the potential to be every bit as large as California earthquakes," says Rix.  "But, small to moderate size earthquakes happen less frequently in the New Madrid zone."

The New Madrid zone was the site of three earthquakes about 200 years ago.  From December 1811 to February 1812 three quakes, all estimated to be 7.7 or stronger magnitudes quakes, struck the area.  While the human toll was minimal, because of the sparse population, the quakes were strong enough to change the course of the Mississippi River, pushing it miles to the east.

Another major earthquake fault lies not too far to our east, and had a major quake hit about 125 years ago.

"In 1886 there was a magnitude estimated to be 7.3 earthquake in Charleston, South Carolina," says Rix.  "It was very damaging at the time.  Obviously today it would be even more damaging simply because it has a higher population."

Other major U.S. cities that sit on, or near, major earthquake faults are Seattle and Salt Lake City.  Even cities in the northeast aren't immune from earthquakes.

"In the New England states, as well as southern Canada there, there is an earthquake zone capable of generating sizable earthquakes," he says.

So, what about Atlanta?

"We're a sufficient distance from them that, if there were to be a large earthquake on one of those faults (New Madrid or Charleston), we would not likely see extensive damage here in Atlanta," Rix says.

The nearest major fault to Atlanta is the Eastern Tennessee Seismic Zone, near the border between Alabama and Tennessee.

"That zone, I don't think, is capable of generating earthquakes as large as New Madrid or Charleston," he says.

Atlanta may be immune from major earthquakes, but other cities are not.  Are they prepared in case one hits?  Rix says no.

"In older cities, east coast cities, like St. Louis and Memphis, there are these older buildings, in many cases unreinforced masonry or brick buildings, that are very prone to damage during an earthquake," Rix says.

Building codes are supposed to meet certain standards concerning seismic activity.  But, Rix says, in some cities, especially Memphis, those codes haven't been adopted for new buildings, and retrofitting hasn't been done for older ones.

"There is a resistance to adopt modern seismic building codes that will increase the chances that a building will survive an earthquake," Rix says.  "And, if people are unwilling to adopt seismic building codes for new construction, they're probably even less willing to incur the expense of retrofitting these older structures to make them more seismically resistant."

Engineering advances have enabled building designers to create structures that are intended to save lives, even at the cost of the building itself.

"The seismic code provisions that we have here in the United States, what are they intended to do?" asks Rix rhetorically.  "They're intended to protect life safety.  What they are not intended to prevent is damage to the building.  Those are two different things.

"We could have a building that is heavily damaged and is, essentially, unusable, but did not collapse and kill people," Rix says.  "That's the goal.  So, here in the United States, we've done a good job of developing these codes with life safety in mind."

"It's our great hope that a large earthquake, near a U.S. city would have a minimal loss of life because the code was intended to specifically prevent the loss of a large number of lives through building collapses, like we're seeing in Port au Prince," he says.

As for the threat of a massive quake hitting near Seattle, or Salt Lake City, or St. Louis, or Charleston, or Memphis, Rix, and others, believe it's not a question of if, but when. 

"We, naively, ignore, these less frequent, but, potentially, much more catastrophic events," he says.  "Eventually that's going to catch up with you.  At some time and at some place, that's going to catch up with us."

Rix says people in places like Memphis might be complacent because their city hasn't been hit by a major quake in nearly 200 years.  Of course, the same was true for Port au Prince.

"Someone in Haiti was probably saying the same thing two weeks ago."