California's Bay Area experienced its strongest earthquake in decades this week, when a 6.0-magnitude earthquake hit Napa County. Over 100 people have been treated for injuries, but no deaths were reported. Earthquakes are much, much more deadly in other parts of the world. Earlier this month, a 6.1-magnitude earthquake killed hundreds in Southwestern China. The video above explains why.

Produced by Joss Fong and Joe Posner

Images courtesy of Getty, AFP, and China Foto Press