Friday's earthquake in Japan was the world's fifth most powerful since 1900, but most of the nation's buildings are still standing in the wake of Friday's ultra-strong earthquake, having suffered only minimal damage.
How did they come through the shaker in such good shape?
Structural engineer Bill Faschan, who's designed cutting-edge commercial towers, hotels, sports stadiums and museums around the world, says some of the strictest building codes in the world were up to the task.
He noted on "The Early Show on Saturday Morning" that Japan is part of the Pacific's "Ring of Fire" of nations especially vulnerable to powerful temblors, which is why Japanese codes are so tough.
The Ring of Fire, he told co-anchor Russ Mitchell, is "a very active seismic center. It's one of the most active in the world. So it presents real challenges, particularly, to design major building structures."
Japanese building codes, Faschan says, "are very comparable to American codes. They bring together the best knowledge in the world to date on how to resist seismic events. And I think you've seen that in the behavior of the buildings in Tokyo."
That city's tall buildings literally swayed as the quake shook the ground.
"They're supposed to sway," Faschan pointed out. "The basic idea, particularly (for) a tall building, is it's supposed to act like a tree. A tree in the wind, it sways back and forth. And in a seismic event, it's very similar. Obviously, the ground (is) shaking as opposed to the building being moved back and forth by the wind, but (it's) the same idea. It's supposed to move. It's supposed to give."
Faschan says he's not surprised by the lack of damage in Tokyo, though, "There could be more severe effects in Tokyo (from a future quake) than we're seeing from this particular quake, because (this one) was at some distance from the city. There are faults that are closer that could have lesser energy released, but because they're closer, they have more impact."
He added he's impressed by how buildings in Tokyo held up, saying, "It's very satisfying for me to see that you can protect life in that way and that everything we try to do works."
Pointing to a model of a building he designed in Ho Chi Minh City in Vietnam, Faschan explained that, "It's not so much size, to use that term, but its height. In other words, if you have a short building, you can maybe imagine that it's pretty stiff. If the ground moves, it moves right along with it. But if you go back to the tree analogy, if you have a tall building ... this one at certain angles is very slender, so it acts like a tree. It will bend. It will give, and it won't break. So that's the nature of taller buildings. They're actually safer. You wouldn't necessarily think that."
How much extra does it cost to construct a building that's quake-resistant?
"In real terms, it's not that big a premium. And it's a small percentage. Probably, in terms of the cost of the overall building, maybe 5 percent, 10 percent, depending on where you are. The percentage will be higher in a place like Japan, than say here in New York."
Why was it that the quake in Haiti, which was much less powerful, leveled so many structures?
"The problem in a place like Haiti is there's not as much modern building construction. A lot of what's built is relatively stout, you know, it's both ... heavy, and it's a little fragile. And it's kind of weak. I mean, that's the nature of, you know, masonry construction, which is what predominates in a lot of places around the world like Haiti. And unfortunately, a lot of it's not modern, so it doesn't take advantage of what has been learned, say, over the course of our lifetime."