Risk of fresh Haiti earthquake could be greater than previously thought
Scientists had thought the Haiti earthquake a year ago released stress on a well-known fault. It didn't. Instead, it revealed faults that scientists didn't know existed.
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Instead, after reviewing seismic information, along with information from satellites and boots-on-the-ground visits to various locations in the area, the team found that the landscape between the fault and the coast has been raised by as much as two feet. Once-submerged corals along the coast were now high and dry.Skip to next paragraph
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That suggested a hidden thrust fault, a conclusion borne out by modeling experiments built on the data the team collected.
"Most or all of the slip was on the Leongane fault," says Carol Prentice, an earthquake scientist at the US Geological Survey's office in Menlo Park, Calif., and another member of the team. But, she cautions, it's a modeled fault and will require more study to determine if it truly has a real-world counterpart.
A different group, same result
In follow-up studies using the presence of the newly proposed fault as a starting point, a group led by Jian Lin of the Woods Hole Oceanographic Institution calculated the effect the quake had on strain along the Enriquillo-Plantain Garden fault. They found that the quake had increased strain along the fault to the east and west of the Leongane fault's rupture zone.
The eastern segment runs past Port-au-Prince a scant three miles from the city center.
"That is a major concern," Dr. Lin says.
But a few months ago, he continues, an analysis of aftershock data revealed something new: another possible fault on the sea floor not far offshore from Haiti's capital.
The fault's capacity for large earthquakes and how frequently the occur are unknown, he says.
Researchers say they hope data from a seismic monitoring network they have established there will help resolve many of the remaining questions scientist have about the area's earthquake risk.