Evidence of the Jan. 12 earthquake in Haiti remains. On land, buildings are destroyed and coral becomes stranded above sea level. In the sea, the water is murky from the displaced mud. An MU researcher and a graduate student were members of a team that went on a 20-day research cruise off the coast of Haiti after the earthquake. The information gathered during the trip will help officials rebuild Haiti.
The scientists wanted to understand which segments of the earthquake fault ruptured and how much fault movement and uplift of coastal features occurred in locations along or near the fault. Colleagues working at the same time on land discovered that some areas of the Haitian coast had been uplifted almost a foot and a half, while other areas had dropped.
“The coast in this region has been uplifted, while other areas had dropped, which indicated that some faults had not yet been mapped,” says Milene Cormier, assistant professor geophysics and geodynamics. “When mapping the underwater extension of the faults, we can determine where it hasn’t ruptured at the seafloor in the last earthquake. This could be used to forecast what might happen there next.”
Mapping the faults will help people make better decisions about rebuilding the capital city, Cormier says. The research team took a seafloor sonar survey of the area that is being considered for a new port and will determine if it could be a better location.
“The team working onshore was constantly communicating with our team surveying offshore,” Cormier says. “Understanding what happened both on land and underwater during the earthquake gives us a more complete picture of what may happen in the future. Scientists from many different universities around the world and from U.S. agencies have been collaborating constructively since the Jan. 12 earthquake and are racing to understand what happened.”
The National Science Foundation Rapid Response Research program funded the research team that used multibeam, sub-bottom profiler, and side scan sonar equipment to map the seafloor surrounding the Enriquillo-Plantain Garden Fault, a system of faults which runs along the southern side of the Dominican Republic and Haiti.
Researchers produced sonar images of the seafloor and seismic profiles that revealed the 3-dimensionl geological structures to about 50 meters below the seafloor. During the trip, researchers also gathered sediments and other evidence from the seafloor that might reveal hidden structures, how the Earth’s plates have moved and where strain may be building now.