Haiti is at risk from further earthquakes, scientists have warned as they discover another fault line in Port-au-Prince.
The 7.0 magnitude quake left more than 200,000 people dead and 1.5 million homeless.
A previously unmapped fault line was found to be responsible for the earthquake that shook the Caribbean island on January 12, this year. The 7.0 magnitude earthquake, which struck the Port-au-Prince area of Haiti, left more than 200,000 people dead and 1.5 million homeless. Research, published in this month’s issue of Nature Geosciences, found the Enriquillo fault, which was previously blamed for the quake, did not release any of its accumulated seismic energy and still poses a threat to Haiti. Seismic threat Eric Calais, who led the research team from Purdue University, Indiana, US said, “This means that the Enriquillo fault is still capable of producing large earthquakes” and “remains a significant threat for Haiti, and Port-au-Prince in particular.” Movement of the Earth’s crust after an earthquake has the potential to reduce or increase pressure on surrounding fault lines. It is unknown whether the earthquake along this new fault line, named the Léogâne fault, has advanced or delayed the next earthquake along the Enriquillo fault. “For practical purposes, speculating on when the next earthquake might happen is not an effective strategy,” Calais said. “We rather need to focus attention, energy and funds on proactive measures to help the country adapt to earthquake hazards.” With a death toll over 200,000 the January 12 earthquake was twice as lethal as any previously recorded 7.0 magnitude quake. The high death toll has been attributed to, among other things, the poor materials and engineering used in construction. Calais believes that such high death tolls can be prevented in the future, “We know enough already to recommend proactive measures to adapt the country to earthquake hazard and, eventually, reduce economic losses and save lives,” Research Co-author Andrew Freed said the lack of surface-rupture, the breakage of ground above a fault line, led to the hunt for a new fault. “It was a big surprise that we couldn’t find a surface rupture anywhere,” Freed said. “We did find other physical changes that we expected after an earthquake of that magnitude, but in entirely the wrong location to have come from the Enriquillo fault.” The team of geologists used a global positioning system and radar interferometry to measure how much the ground moved during the earthquake. Computer modelling allowed the team to determine what characteristics a fault must have to produce the observed movements. These characteristics led to the discovery of the previously unmapped Léogâne fault. The team are to keep taking measurements over the next few years in an attempt to pinpoint areas which are under threat of an earthquake. The full report can be found at nature.com