Why earthquakes are so devastating to Haiti

A bulldozer removes debris at the site of the collapsed Hotel Le Manguier in Les Cayes, Haiti, on Aug. 16, 2021. Photo: The Associated Press
By Robert C. Jones Jr.

A bulldozer removes debris at the site of the collapsed Hotel Le Manguier in Les Cayes, Haiti, on Aug. 16, 2021. Photo: The Associated Press

Why earthquakes are so devastating to Haiti

By Robert C. Jones Jr.
Complex geology combined with structures that are not resistant to earth tremors make the island nation especially vulnerable to the effects of earthquakes, University of Miami experts say.

This time, the location was different, but the result the same: flattened buildings, mass casualties, people trapped beneath rubble, and hospitals overwhelmed by thousands of injured people. 

The powerful 7.2 magnitude earthquake that devastated the cities of Jérémie and Les Cayes on Haiti’s southern peninsula in the morning hours of Aug. 14 immediately drew comparisons to the powerful temblor that rocked the country’s commercial center, Port-au-Prince, more than 11 years ago. 

Both earthquakes illustrate the complex geology at work that makes the island and, indeed, that region of the Caribbean so susceptible to tremors. 

Haiti is located near the intersection of two, massive tectonic plates: the North American plate and the Caribbean plate. These plates move past each other over time, and a series of fault lines between them cut through the island of Hispaniola, which is divided by Haiti and the Dominican Republic. 

“It is a tectonically complex area,” said Falk Amelung, a professor of marine geosciences at the University of Miami’s Rosenstiel School of Marine and Atmospheric Science. “In addition to transform motion, Hispaniola is contracting by 2 to 5 millimeters a year in north-south direction, and it has subduction zones both in the north and in the south.”

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Haiti Special Report: Five years after the Jan. 12, 2010 earthquake.

 The Aug. 14 quake occurred along the central section of the Enriquillo-Plantain Garden fault zone, a major system of left-lateral, strike-slip faults that run along the southern side of Hispaniola, according to Amelung. Previous earthquakes along this fault struck Haiti in 1751 and 1770, destroying Port-au-Prince, he noted.

“The recent earthquake increased the stress along the fault segments to the west and east of the rupture zone, making these segments likely sources of future earthquakes and increasing the seismic hazard for Port-au-Prince to the east,” Amelung explained. The 2010 temblor, he said, occurred along a fault north of the Enriquillo-Plantain Garden fault, leaving it highly stressed. 

The epicenter of the recent quake occurred about 7.5 miles northeast of Saint-Louis-du-Sud. The tremor, more powerful than the 7.0-magnitude quake that hit Haiti in 2010, was felt in neighboring Dominican Republic and as far away as Cuba and Jamaica, which isn’t unusual, according to Amelung. “Earthquakes that are magnitude 7 and greater are always felt up to a few hundred kilometers away,” he pointed out.

The quake is especially devastating to Haiti’s southern region. Hurricane Matthew struck the region in 2016, killing hundreds of people and causing widespread damage.

More than 1,940 people died in this past Saturday’s earthquake, with thousands injured, Haiti’s Civil Protection Agency reported. And Tropical Storm Grace dumped torrential rains on the island, complicating rescue efforts.

“I am worried about landslides,” Amelung said. “The shaking during the earthquake has loosened the ground, and heavy rainfall may lead to acceleration of unstable slopes. And large aftershocks could trigger catastrophic landslides.” 

But the catastrophe now being witnessed in Haiti is as much a result of construction practices on the island as it is a consequence of the complex geology.

Powerful temblors in Haiti are especially devastating because many structures on the island are built using unreinforced concrete, which is adequate to weather the power of a hurricane but deficient when it comes to withstanding earthquakes, said Christian C. Steputat, a forensic engineer specializing in structural, geotechnical, and materials engineering, who is a Ph.D. candidate in the College of Engineering. 

And more than 11 years after the 2010 earthquake, Haiti still has no uniform building code to ensure that structures are earthquake-resistant, noted Steputat, who has worked on design and construction projects in Haiti and the Dominican Republic.

Other Caribbean nations have adopted strict building codes, he said, noting that the Dominican Republic recently ramped up construction standards for building projects on its side of Hispaniola. Haiti could significantly minimize future damage to its infrastructure if it were to do the same. “Political unrest and socioeconomic conditions make it challenging to do so,” he said, “but an effort that involves many partners could make it happen.”