What type of fault caused the Haitian earthquake in January 2010?

Answer 1

The name of the fault line responsible for the January 2010 Haitian earthquake is the Enriquillo-Plantain Garden Fault. It is a strike-slip fault, like the San Andreas Fault in California. Movement occurs horizontally.

This fault along with the Oriente and Septentrional Fracture Zones to the north of Haiti are part of the transform boundary that separates the Caribbean and North American plates where the Caribbean plate is moving eastwards by about 20 mm/year relative to the North American plate.

However the Enriquillo-Plantain Garden fault has been locked for approximately 250 years. As such this movement has caused localised stresses to accumulate in the Earth's crust around the locked fault zone over time, causing energy to be stored in the form of elastic strain or elastic potential energy (like that in a compressed spring). Ultimately this stress has exceeded the shear strength of the crust in the fault zone causing a sudden brittle failure or rupture. This in turn causes movement and a sudden release of the stored elastic strain energy in the form of seismic waves (as well as heat and sound).

This ultimately resulted in a rupture of the Enriquillo-Plantain Garden Fault that was approximately 65 km (40 miles) in length with an average slip of 1.8 m (5.9 ft).

Please see the related question for more information.