On the anniversary of the January 12th, 2010, magnitude 7.0 earthquake in Haiti, it’s crucial to reflect on the plate tectonic context and the profound human impact of this event. The Caribbean Plate shifts eastward at about 2 centimeters per year relative to the North American and South American Plates. The boundary between the North American and Caribbean Plates, particularly in the Greater Antilles, is a zone of distributed deformation, segmented into at least four microplates. These microplates facilitate the transition of the North American-Caribbean plate boundary from strike-slip in the Cayman Trough, between Cuba and Jamaica, to oblique collision between Hispaniola and the Bahama Platform, and further to oblique subduction at the Puerto Rico Trench, leading to subduction at the Lesser Antilles Trench.
The largest of these microplates is the Gonâve microplate, which stretches from the Cayman Spreading Center to western Hispaniola in Haiti. The Gonâve microplate is bordered by the Septentrional Fault to the north and the Enriquillo Fault to the south, both of which are predominantly left-lateral strike-slip faults, moving at a long-term rate of about 1 centimeter per year. Significant earthquakes were recorded on the Enriquillo Fault in 1751 and 1770, followed by major earthquakes on the Septentrional Fault in 1842 and 1887. Over the next centuries, Port-au-Prince grew into a city of over three million people. Then, with little warning, the magnitude 7.0 earthquake struck on the Léogâne Fault, just north of the Enriquillo Fault. The epicenter was a mere 16 kilometers from Port-au-Prince. The rupture started at a depth of 12 kilometers and progressed westward, reaching a maximum fault displacement of 5 meters at a depth of 5 kilometers.
The ground shaking in Port-au-Prince was severe, with liquefaction occurring in port areas and landslides affecting hilly regions. Over the following 12 days, at least 52 aftershocks, with magnitudes greater than 4.5, were recorded. The human toll of the 2010 Haiti earthquake was devastating, with estimates ranging from 100,000 to over 200,000 deaths. Over one million people were left homeless. This earthquake was the fourth deadliest in the past 100 years and caused five times more fatalities than any historical earthquake of similar magnitude.
Why was this earthquake so deadly? In one word: construction. While concrete and cinderblock buildings can withstand hurricane-force winds, they are highly susceptible to earthquake-induced ground shaking. Many structures collapsed because the lightly reinforced or unreinforced concrete columns and masonry-block walls couldn’t support the heavy concrete slabs of the floors and roofs. However, modern buildings, such as one located across the street from the hospital, remained virtually undamaged, showcasing the effectiveness of earthquake-resistant design and construction.
In addition to the overcrowded conditions, Haiti is the poorest country in the Western Hemisphere. This poverty, coupled with the island’s remoteness, made cleanup a monumental challenge. Furthermore, rebuilding using the best, and therefore most expensive, construction materials and methods was economically unfeasible. Despite these challenges, significant steps were taken to improve earthquake resilience during the recovery phase. Efforts by the Haitian government and non-governmental organizations like GeoHazards International and Build Change focused on training locals to integrate cost-effective earthquake-resistant designs into rebuilding and new construction efforts.
The tragic losses in Haiti offer a stark lesson to other earthquake-prone regions worldwide: how buildings are constructed matters. Engineering structures and infrastructure to withstand earthquake shaking can save lives, preserve property, and help communities recover more quickly when disaster strikes.
