Five ways to trigger a natural disaster

Human activities can trigger natural disasters such as earthquakes and flooding.

“Dams are the most dangerous man-made structure likely to cause quake,” says David Booth of the British Geological Survey. By artificially holding a large volume of water in one place, dams increase pressure on fractures beneath the surface of the earth. What’s more, water has a lubricating effect, making it easier for the fractures — or faults — to slip.

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