Haiti must prepare for more massive quakes: scientists
Pastor Dale Morgan
Haiti must prepare for more massive quakes: scientists*
MIRA OBERMAN
January 17, 2010 - 7:49AM
Haiti and its neighbours must prepare themselves for more massive quakes
after the devastating tremors this week increased pressure along a
lengthy fault line, scientists warned Friday.
Paul Mann, a senior research scientist at the Institute for Geophysics
at the University of Texas at Austin, warned that just because the
rebuilding process had started people shouldn't assume the risk was over.
"This relief of stress along this area near Port-au-Prince may have
actually increased stress in the adjacent segments on the fault," he
told AFP.
Researchers have already begun to work on models to try to predict how
the stress changes resulting from the 7.0-magnitude quake which struck
Tuesday is affecting the adjacent segments of the fault.
"This fault system is hundreds of kilometers long and the segment that
ruptured to form this ear quake is only 80 kilometers long," Mann said
in a telephone interview.
"There are many more segments which are building up strain where there
haven't been earthquakes for hundreds of years.
"Potentially any one of these segments could cause an earthquake similar
to that which happened in Haiti."
There are, thankfully, only two major population centers along the
fault: Port-au-Prince and Kingston, Jamaica.
But as demonstrated in the chaos which followed Tuesday's tremor, the
impact of a quake of that magnitude can be "paralyzing," Mann said.
Adding to the danger is the fact that the segment which broke was not
among those closest to Port-au-Prince.
And there is a second fault system in the north of Haiti which extends
to the Dominican Republic which has not ruptured in 800 years and has
built up sufficient pressure for a 7.5 magnitude quake.
"The question is when are those going to rupture," Mann said, adding
that it is very difficult to predict "whether or not that's going to
happen next week or 100 years."
Eric Calais, a French geophysicist who works at Purdue University in
Indiana, is among those trying to assess the danger.
He had warned Haitian officials years ago of dangerous pressure in the
fault which caused this week's devastating quake, but little could be
done to reinforce the desperately poor nation's weak buildings.
"The Haitian government is not to blame in this," Calais told AFP.
"They listened to us carefully and they knew what the hazard was. They
were very concerned about it and they were taking steps. But it just
happened too early."
Calais began researching the fault line in 2003 and soon took his
initial findings to the Haitian government, even meeting with the prime
minister.
In March 2008 he and Mann presented a paper showing that the fault had
built up sufficient pressure to cause a 7.2 magnitude quake.
But they could not pinpoint when the quake might strike and the
government was occupied with recovering from a series of four hurricanes
which struck that year.
While the government had begun work on an emergency response plan,
little could be done to retrofit and strengthen key buildings such as
hospitals, schools and government buildings from which rescue operations
could be organized.
"It's a poor country," Calais said. "Strengthening a building to resist
a large earthquake can be as costly as replacing the building."
The devastation will allow Haiti to rebuild stronger than before, Calais
said, noting that there are relatively cheap engineering solutions that
can be applied to ensure that new buildings will not collapse in the
next quake.
"It's very important for Port-au-Prince to rebuild properly," he added.
"There are other segments of that fault that could rupture in the future."