The Science Behind the 2010 Haiti Earthquake

The Science Behind the 2010 Haiti Earthquake

On January 12th, 2010, a country long devastated by corrupt leadership and extreme poverty was dealt another blow. A magnitude 7.0 earthquake struck Haiti, killing approximately 250,000 people and displacing another 1.5 million. In terms of magnitude, this earthquake wasn't very remarkable; in fact, there were 17 larger earthquakes in 2010 alone. Haiti's lack of economic resources and reliable infrastructure, however, made this one of the deadliest earthquakes of all time.

Geologic Setting

Haiti makes up the western portion of Hispaniola, an island in the Greater Antilles of the Caribbean Sea. The island sits on the Gonâve microplate, the largest of four microplates that lay between the North American and Caribbean plates. Although the area isn't as prone to earthquakes as the Pacific Ring of Fire, geologists were aware that this area posed a risk.

Scientist initially pointed to the well-known Enriquillo-Plantain Garden fault zone (EPGFZ), a system of strike-slip faults that make up the Gonâve microplate - Caribbean plate boundary and were overdue for an earthquake. As months passed, however, they realized the answer was not so simple. Some energy was displaced by the EPGFZ, but most of it came from the previously unmapped Léogâne fault. Unfortunately, this means that the EPGFZ still has a sizable amount of energy waiting to be released.


Although tsunamis are often associated with earthquakes, Haiti's geologic setting made it an unlikely candidate for a massive wave. Strike-slip faults, like those associated with this quake, move plates side-to-side and don't normally trigger tsunamis. Normal and reverse fault movements, which actively shift the seafloor up and down, are usually the culprits. Furthermore, the small magnitude of this event and its occurrence on land, not off the coast, made a tsunami even more unlikely.

Haiti's coast, however, has a large buildup of coastal sedimentation - the country's extreme dry and wet seasons cause vast amounts of sediment to travel from the mountains to the ocean. To make matters worse, there had not been a recent earthquake to release this buildup of potential energy. The 2010 earthquake did just that, causing an underwater landslide that triggered a localized tsunami.


Less than six weeks after the devastation in Haiti, a magnitude 8.8 earthquake struck Chile. This quake was approximately 500 times stronger, yet its death toll (500) was only five percent of Haiti's. How could this be?

For starters, the Haiti earthquake's epicenter was located only nine miles from Port-au-Prince, the country's capital and largest city, and the focus occurred a shallow six miles underground. These factors alone could be potentially catastrophic anywhere around the world.

To compound matters, Haiti is vastly impoverished and lacks proper building codes and sturdy infrastructure. Residents of Port-au-Prince used whatever construction material and space was available, and many lived in simple concrete structures (it is estimated that 86 percent of the city lived in slum conditions) that were immediately demolished. Cities at the epicenter experienced X Mercalli intensity.

Hospitals, transportation facilities and communication systems were rendered useless. Radio stations went off the air and nearly 4,000 convicts escaped from a Port-au-Prince prison. Over 52 magnitude 4.5 or greater aftershocks crippled an already devastated country in the following days.

Unheard of amounts of aid poured in from nations around the world. Over 13.4 billion dollars were pledged to relief and recovery efforts, with United States contributions making up nearly 30 percent. The damaged roads, airport and seaports, however, made relief efforts extremely difficult.

Looking Back

Recovery has been slow, but the country is gradually returning to normal; unfortunately, "normalcy" in Haiti oftentimes means political turmoil and mass poverty. Haiti still has the highest infant mortality rate and lowest life expectancy of any country in the Western Hemisphere.

Yet, there are small signs of hope. The economy has improved, helped by debt forgiveness from institutions around the world. The tourism industry, which was beginning to show signs of promise before the earthquake, is slowly returning. The CDC has helped make vast improvements to Haiti's public health systems. Still, another earthquake to the area anytime soon would result in terrible consequences.