Charting Fault Underwater Documents How Haitian Coast Was Uplifted During Quake, Exposing Corals Above Sea Surface
MU researcher and student were part of a team that examined the underwater extension of the faults responsible for the Haiti earthquake
April 14th, 2010
Researchers wanted to understand which segments of the earthquake ruptured and how much fault movement and uplift of coastal features occurred in locations along or near the fault.
COLUMBIA, Mo. – 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. A University of Missouri 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 National Science Foundation (NSF) 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.
“The coast in this region has been uplifted, while other areas had dropped, which indicated that some faults had not yet been mapped,” said Milene Cormier, assistant professor geophysics and geodynamics in the MU College of Arts and Science. “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 said. 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 said. “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 January 12 earthquake and are racing to understand what happened.”
The NSF-owned Research Vessel (R/V) Endeavor carried the researchers from MU, Columbia University, the University of Texas at Austin and the University of California at Santa Barbara.
The trip also served as a humanitarian aid effort. Dozens of large tents supplied by the organization -“Plan USA,” were delivered to serve as transitional classrooms and provide safe zones for children in camps in the affected areas.