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?<br /><br />Click here to subscribe to The Economist on YouTube: http://econ.trib.al/rWl91R7 <br /><br />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.<br /><br />How do you make a building earthquake-resistant?<br /><br />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. <br /><br />Avoid using brittle materials like concrete or wood. <br />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.<br /><br />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.<br /><br />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.<br /><br />Some modern buildings are fitted with damping systems. These devices help dissipate vibrations produced by a quake. <br /><br />You can make buildings survive an earthquake but whether you do is dependent on much more than bricks and mortar.<br /><br />Daily Watch: mind-stretching short films throughout the working week.<br /><br />For more from Economist Films visit: http://films.economist.com/ <br />Check out The Economist’s full video catalogue: http://econ.st/20IehQk <br />Like The Economist on Facebook: https://www.facebook.com/TheEconomist/ <br />Follow The Economist on Twitter: https://twitter.com/theeconomist <br />Follow us on Instagram: https://www.instagram.com/theeconomist/ <br />Follow us on LINE: http://econ.st/1WXkOo6 <br />Follow us on Medium: https://medium.com/@the_economist
