Iran straddles a major geological fault line, making it prone to seismic activity.

BBC: Iran: Dozens of aftershocks follow deadly earthquake

Long known to stand above a geological fault, the stadium was declared unsafe in a seismic review, said Barbour, who added that about 70% of the project's construction cost comes from safety upgrades.

WSJ: Cal's Football-Stadium Gamble

It was built over a geological fault.

ECONOMIST: A bit more cut off from the world

Extrapolating from Dr Freund's laboratory experiments, the strain in a real-life geological fault such as the San Andreas could, as it shifted, generate hundreds of thousands of amperes per cubic kilometre in a fluctuating pattern that would cause very low frequency radio waves to be emitted, thus disrupting the ionosphere.

ECONOMIST: Predicting earthquakes

Saturday's quake occurred along the Longmenshan fault line, which was also the source the 2008 quake, according to the U.S. Geological Survey.

WSJ: Quake Kills More Than 100 in Sichuan