How to survive an earthquake through clever engineering

When earthquakes strike, the most dangerous aspect is not the shaking ground, but the risk posed by falling debris. So how do you make a structure earthquake-resistant?

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More than a million people have died in earthquakes in the past two decades. But earthquakes don't pose the greatest risk: collapsing buildings do.

How do you make a building earthquake-resistant?

Make the roof the lightest part. In 2008 a quake in the chinese province of Sichuan killed more than 80,000. Top-heavy tiled roofs were found largely to blame.

Avoid using brittle materials like concrete or wood.
Steel frames are flexible and absorb shock so won't shatter or snap. Stress-test the building on a "shake table" to expose any structural weaknesses.

The world's biggest and best skyscrapers resist side-to-side buffeting using "shear" walls, a system of panels and braces that channel a side-to-side force downward into the building's foundations to stabilise it.

Ancient Japanese architects fitted pagodas with a shinbashira, a giant central pole that absorbs the forces from the main structure. In 1995, than Hanshin earthquake in Japan destroyed more than 100,000 buildings but every pagoda in the area survived.

Some modern buildings are fitted with damping systems. These devices help dissipate vibrations produced by a quake.

You can make buildings survive an earthquake but whether you do is dependent on much more than bricks and mortar.

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