The geology behind the tragic Haitian earthquake

The Christian Science Monitor had an excellent piece yesterday on the complicated geology of Hispaniola, the island shared by Haiti and the Dominican Republic.  Two strike-slip faults, similar to the famous San Andreas fault of California, run through Haiti due to the movements of the North American and Caribbean Plates.  While the Easterly Lesser Antilles were formed due to subduction of the more dense North American Plate under the Caribbean plate, both plates are of equal density near Hispaniola, leading to a slip fault instead.  Built up pressure in the fault led to this week's terrible earthquake, and further research is needed to better understand and predict future movements of these faults.