 The quake occurred in the vicinity of the northern boundary where the Caribbean <unk> plate shifts eastwards by about 20 mm ( 0 @.@ 79 in ) per year in relation to the North American plate . The strike @-@ slip fault system in the region has two branches in Haiti , the Septentrional @-@ Oriente fault in the north and the Enriquillo @-@ Plantain Garden fault in the south ; both its location and focal mechanism suggested that the January 2010 quake was caused by a rupture of the Enriquillo @-@ Plantain Garden fault , which had been locked for 250 years , gathering stress . However , a study published in May 2010 suggested that the rupture process may have involved slip on multiple blind thrust faults with only minor , deep , lateral slip along or near the main Enriquillo – Plantain Garden fault zone , suggesting that the event only partially relieved centuries of accumulated left @-@ lateral strain on a small part of the plate @-@ boundary system . The rupture was roughly 65 km ( 40 mi ) long with mean slip of 1 @.@ 8 metres ( 5 ft 11 in ) . Preliminary analysis of the slip distribution found <unk> of up to about 4 m ( 13 ft ) using ground motion records from all over the world . 
