Explainer: Why Haiti is prone to devastating earthquakes

Earthquakes have been wreaking havoc in Haiti since at least the 18th century when the city of PortauPrince was destroyed twice in 19 yearsAugust 14th powerful quake killed hundreds and injured thousands more Eleven years earlier a temblor killed tens of thousands of people if not hundreds of thousands Haiti sits near the intersection of two tectonic plates that make up the Earths crust Earthquakes can occur when those plates move against each other and create frictionHaiti is also densely populated Plus many of its buildings are designed to withstand hurricanes not earthquakes Those buildings can survive strong winds but are vulnerable to collapse when the ground shakesWhat makes Haiti prone to earthquakesThe Earths crust is made up of tectonic plates that move And Haiti sits near the intersection of two of them iquest the North American plate and the Caribbean plateMultiple fault lines between those plates cut through or near the island of Hispaniola which Haiti shares with the Dominican Republic Whats worse not all of those fault lines behave the same wayHispaniola sits in a place where plates transition from smashing together to sliding past one another said Rich Briggs a research geologist at the US Geological Surveys Geologic Hazards Science Center Its like a rock stuck in the track of a sliding glass door he said It just does not want to move smoothly because its got so many different forces on itWhat caused the most recent quakeSaturdays magnitude 72 earthquake likely occurred along the EnriquilloPlantain Garden fault zone which cuts across Haitis southwestern Tiburon Peninsula according to the USGS Its the same fault zone along which the devastating 2010 earthquake occurred And its likely the source of three other big earthquakes in Haiti between 1751 and 1860 two of which destroyed PortauPrinceEarthquakes are the result of the tectonic plates slowly moving against each other and creating friction over time said Gavin Hayes senior science adviser for earthquake and geologic hazards at USGS That friction builds up and builds up and eventually the strain thats stored there overcomes the friction Hayes said And thats when the fault moves suddenly Thats what an earthquake isWhy can earthquakes in Haiti be so devastatingIts a combination of factors that include a seismically active area a high population density of 11 million people and buildings that are often designed to withstand hurricanes not earthquakesTypical concrete and cinder block buildings can survive strong winds but are vulnerable to damage or collapse when the ground shakes Poor building practices can also play a role The 2010 quake hit closer to densely populated PortauPrince and caused widespread destruction Haitis government put the death toll at more than 300000 while a report commissioned by the US government placed it between 46000 and 85000I think its important to recognize that theres no such thing as a natural disaster said Wendy Bohon a geologist with Incorporated Research Institutions for Seismology What you have is a natural hazard that overlaps with a vulnerable systemWhat does the future holdGeologists say they cannot predict the next earthquake But we do know that earthquakes like this can cause similarsized earthquakes on the next portion of the fault said Hayes of USGS And its quite a significant hazard in places that dont have the construction practices to withstand the shakingAlso Read Death toll from Haiti earthquake is over 700Construction of more earthquakeresistant buildings remains a challenge in Haiti which is the poorest nation in the Western Hemisphere Before Saturdays quake Haiti was still recovering from the 2010 earthquake as well as Hurricane Matthew in 2016 Its president was assassinated last month sending the country into political chaos And while there have been some success stories of Haitians building more earthquakeresistant structures the country has lacked a centralized effort to do so said Mark Schuller a professor of anthropology and nonprofit and NGO studies at Northern Illinois UniversityHaitis government has become increasingly weak while nongovernmental organizations focus on their own compartmentalized projects There is technical knowledge in Haiti There are trained architects There are city planners Thats not the problem Schuller said The problem is a lack of funding for coordination and lack of political will from donors to organizations providing aid