(ABC News) The 7.0 magnitude earthquake that hit Haiti at 4:53 p.m. Tuesday, displacing and possibly killing thousands of people, was the most violent quake the country had experienced in more than a century, according to the U.S. Geological Survey.
The quake occurred along the fault line that separates the Caribbean and North American tectonic plates. It is a strike-slip fault line, and it runs east to west through Haiti, the government agency said.
When the quake hit, the massive plates, located about 10 miles southwest of the densely populated capital, Port-au-Prince, moved horizontally, causing the pieces of rock to move past each other.
"The North American and Caribbean tectonic plates are sheering the island, crushing it, grinding it and, as that occurs, earthquakes pop off," Michael Blanpeid, associate coordinator for the Geological Survey's Earthquake Hazards Program, said in a podcast on the agency's Web site Tuesday.