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Lauren Admire | 18 Jan 2010 17:00

Complex, Active Fault Lines Created Devastating Haitian Earthquake

The Haitian earthquake that devastated the country and resulted in ever-growing death tolls was caused by an active tangle of tectonic faults in the Caribbean and North American crustal plates.

According to Jian Lin, a Woods Hole Oceanographic Institution scientist, the quake was "large, but not huge." However, it caused so much damage because of three factors: First, the quake was centered only 10 miles southwest of Haiti's capital, Port au Prince; second, the quake was shallow, about 10-15 km below the land; and third, the Haitian buildings were not built to withstand such force. This resulted in a worst-case scenario for the Haitian people, and Lin states that "it should be a wake-up call for the entire Caribbean."

The quake occurred along a "strike-slip" fault, meaning that connecting plates were sliding in opposite directions. Adjacent faults can stay in place for years, with pressure mounting as each plate tries to move in the opposite direction. In this particular case, the Caribbean Plate was sliding east, and the Gonvave Platelet was sliding west. When enough pressure mounts between the two plates that are pushing against each other, one of them jerks forward, instantly relieving the pressure and resulting in massive amounts of energy that can spawn earthquakes and tsunamis. This same type of fault line exists along California's San Andreas Fault.

Geologists say that aftershocks can be expected in the coming days, weeks, months, years and even decades. Since the stress has been relieved in that particular fault, Lin says that it should not experience another quake of this magnitude for perhaps 100 years.
However, the particular patch of faults that spawned the devastating Haitian earthquake is surrounded by more faults throughout the Caribbean, and those faults are definitely active.

Lin espouses a focus on earthquake education and a reconstruction of houses and buildings that can withstand earthquakes of that magnitude. "A lot of people forget [earthquakes] quickly and do not take the words of geologists seriously," Lin states. "But if your house is close to an active fault, it is best that you do not forget where you live."

To aid in Haitian relief efforts, please visit the Red Cross website for further information. Or play some games!

Source: Science Daily

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