World's Largest Earthquake-Safe Building: Open for Business in Istanbul

"Istanbul Opens World's Largest Earthquake-Safe Building"
Wired Science (November 20, 2009)

"The world's largest seismically isolated building, the new international terminal at Istanbul's Sabiha Gökçen Airport, is now complete and open for business.

"Stretching across more than 2 million square feet, the terminal doesn't sit directly on the soil, but rather on more than 300 isolators, bearings that can move side-to-side during an earthquake. The whole building moves as a single unit, which prevents damage from uneven forces acting on the structure.

" 'What an isolation system does is that it enables the building to move through large displacements in unison, and in doing that, you absorb earthquake energy,' said Atila Zekioglu, the engineer at the firm Arup, who designed the building.

"Earthquakes accelerate buildings laterally, whipping them back and forth. Isolators (see photo below) slow down the motion of the building. In the case of the new terminal, the building will only have to withstand one-fifth of the acceleration that it would have had to without the earthquake proofing...."

Designing with earthquakes in mind makes sense in Istanbul. The city is near where the Arabian, African, and Eurasian continental plates come together. The North Anatolian Fault runs about 15 miles south of the city, and since Earth's crust is pretty much constantly in motion, all three plates are sliding against each other.

Not smoothly. Like other fault lines, the ones in Istanbul's neighborhood stick for a while before jerking into a new position. When that happened on August 17, 1999, the city experienced a magnitude 7.4 earthquake 17,000 people stopped living rather abruptly, and billions of dollars' worth of property was damaged or destroyed.

That sort of thing is incentive to build the next set of buildings to ride out big quakes. One of which, the article says, is more likely than not to happen in the next 30 years or so.

The article shows how the new airport terminal is designed to stay more-or-less in place while the ground gets jerked around under it. That way, there will probably be damage - but a much better chance that the building won't collapse, killing whoever is inside.

Background on plate tectonics and continental drift:

• "Earth Science: Plate Tectonics"
  The astronomy & astrophysics program at Washington State University (May 8, 2000)
• A plethora of illustrations, and a little text, about continental drift
• "Chapter 2 - PHYSICAL GEOGRAPHY OF THE US"
  GEOGRAPHY: USA, Alan A. Lew, (2004)
  • Written from an American point of view, as the title says - but also with a
    • Pretty good discussion of continental drift
    • Rather good map showing "Continental Drift in the past 200 million years"
• "Continental drift and climate"
  E. Linacre & B. Geerts, College of Engineering and Applied Science, Atmospheric Science, University of Wyoming (January, 2002)
• "Research Highlights - Jurassic Quiet Zone Deeptow Magnetics"
  Woods Hole Oceanographic Institution (January 31, 2005)
  • A fascinating article on some of "the oldest surviving ocean crust in the world today"