Posted on 01/23/2010 2:25:48 PM PST by myknowledge
Another earthquake is threatening to hit Haiti with possibly more force than the massive quake that levelled Port-au-Prince, seismologists say.
Aftershocks have already rattled the impoverished Caribbean nation in the days following the January 12 quake that killed over 110,000 people, left nearly 610,000 homeless and injured scores more.
On Wednesday, a magnitude 5.9 quake struck people already scrambling to rebuild their tattered lives.
But more are likely on their way. The US Geological Survey (USGS) estimated on Thursday that there's a 25 per cent probability that one or several magnitude 6 aftershocks could strike in the coming weeks, although they will space out more and more over time.
If the devastating magnitude 7 magnitude quake that hit nearly two weeks ago freed much of the tension accumulated on one portion of the Enriquillo-Plantain Garden fault zone, another segment east of the epicentre and adjacent to Haiti's capital Port-au-Prince has barely moved, according to the USGS.
Yet part of this fault zone accumulated more strain due to the sliding of North American and Caribbean tectonic plates that could unleash all that strength at any moment without warning.
The geological agency based its predictions on preliminary measures of deformations using radar, satellite and aerial imagery.
"We just know from other earthquakes worldwide and from the history of Haiti that large earthquakes can occur close in time," USGS seismologist David Schwartz told AFP on Saturday. "Not one of us would be surprised."
Citing Turkey, which experienced two earthquakes above magnitude seven just three months apart in 1999, Schwartz warned a similar scenario could take place in Haiti.
The Enriquillo fault zone, which runs along the southern portion of the island of Hispaniola shared by Haiti and the Dominican Republic, could generate a tremor measuring up to 7.2 - slightly higher than the original quake - according to Eric Calais, a seismologist at Purdue University.
"Earthquakes in this region tend to repeat themselves in sequences," he said in an interview, noting that similarly large quakes have shaken Haiti at least four times in the past three centuries, including those of 1751 and 1770, which completely destroyed Port-au-Prince.
"Port-au-Prince must be rebuilt according to strict seismic norms."
Some nuclear plants that can resist magnitude 8 earthquakes are now being built, he noted.
The USGS said an in-depth evaluation of the quake risk for Haiti and other Caribbean countries would provide the basis to establish and improve construction norms in order to eventually erect more resistant buildings.
But this would require extensive geological assessments of faults, soil conditions, strain accumulations and studies of recent seismic patterns and activity.
Calais lamented the scant attention seismologists have paid to Haiti in recent years. Only two teams of experts, including one from Purdue University where he teaches, have worked in the country in the past 15 years. They had already warned about the risk of a new powerful quake.
He plans to travel to Haiti on Monday with a battery of instruments to coordinate the first seismic study since the killer quake.
Construction norms for earthquakes are great if you can pay for them. The resources in Haiti are not going to pay for any such standards in construction beyond, perhaps, the presidential palace.That edifice will surely be rebuilt to level 8 standards even if the rest of Haiti has to be starved to do it. Alternatively, tropical thatched huts and wood construction would be indicated except there aren’t any trees in Haiti...
The Devil may yet make another deal with Haiti, or not.
John Edwards may be forced to cut short his mission of mercy.
John Edwards may be forced to cut short his mission of mercy.
generate a tremor measuring up to 7.2 - slightly higher than the original quake -
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This is misleading, the first quake was a 7, the scale is logarithmic so a magnitude 8 is TEN times as powerful as a 7. This means that a 7.2 is MUCH stronger than a 7, not just slightly stronger.
Sounds good to me!
...or in Detroit.
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