Earthquakes are some of the most studied natural disasters, and yet much of their qualities are still shrouded in mystery. Earthquakes strike along fault lines between the 12 tectonic plates when the frictional pressure becomes too much. Throughout history they have devastated cities.

Originally released by BBC Worldwide Learning, 2007. Streaming video file encoded with permission for digital streaming by Infobase on April 18, 2015.

Earthquakes (5:00); --Earthquakes (0:10);.