MIAMI — For years, geologists had been predicting an earthquake in Haiti — possibly as powerful as magnitude 7.2. The problem was they couldn't say when.
"It could have been the next day, it could have been 10 years, it could have been 100," said Miami geophysicist and earthquake expert Dr. Tim Dixon. "This is not an exact science."
Geologists had long warned about seismic pressures building up along the Enriquillo Fault Line that runs from Jamaica eastward through Port-au-Prince, Haiti, and into the Enriquillo Valley in the Dominican Republic. The fault line is part of the boundary between the North American and Caribbean tectonic plates.
The earth is divided into about a dozen tectonic plates that float and shift, moving past each other at geologically slow rates. The North American plate, which includes the U.S. and Canada, moves west relative to the Caribbean plate, at a rate of about an inch a year.
And there was a chilling, if imprecise, prediction in a paper by a group of U.S. geologists presented at the 18th Caribbean Geological Conference in Santo Domingo, Dominican Republic, in March 2008.
That inch-per-year movement had built up to six lateral feet of unrelieved pressure since the last major quake, in the south-central Dominican Republic in 1751. In a reference to Port-au-Prince, the conference report said: "This means that the level of built-up stress and energy in the earth could one day be released resulting in an earthquake measuring 7.2 or more on the Richter Scale. This would be an event of catastrophic proportions in a city with loose building codes, and an abundance of shanty-towns built in ravines and other undesirable locations."
As far back as 1998, Dixon, a professor of geophysics at the Rosenstiel School of Marine and Atmospheric Science, says he and five colleagues published a paper in the Journal of Geophysical Research warning of seismic trouble brewing in Haiti. But again, they couldn't say when.
One geologist, Patrick Charles, formerly of the Geological Institute of Havana, called the danger imminent.
Even then, what could Haiti have done?
Long beset by poverty, political unrest, HIV and chronic hurricanes and floods, Haiti lacked both the technical expertise and the resources to study earthquakes, let alone take action to withstand them, Dixon said.
Dr. Amy Wilentz, a professor of politics at the University of California at Irvine and author of "The Rainy Season: Haiti Since Duvalier," agrees.
"A lot of the buildings are made of bricks and cement and tin roofs," she said.
"It's hard to envision programs like the ones we have in California to reinforce buildings and do earthquake stabilization, much less projects to make new buildings safe. It's hard enough to put up a building at all; the idea of making it perfect is Kafka-esque."
Asked Susan Purcell, director of the Center for Hemispheric Policy at the University of Miami: "This is the poorest country in the hemisphere; what are they supposed to do and with what resources? . . . Most of them are dirt-poor and living in makeshift houses."
Richer countries can do a lot to mitigate damage from earthquakes, but even they can't entirely prevent it, experts say. In California, building codes have become stricter after each earthquake from the San Fernando quake in 1971, the Loma Prieta quake in 1989 and the Northridge quake in 1994, says Jeanne Perkins, an earthquake consultant for the Association of Bay Area Governments in San Francisco.
Even then, insurance-company estimates say that if a 7.0 quake like the one that hit Port-au-Prince happened today in San Francisco, it would render 150,000 buildings uninhabitable and kill hundreds or thousands of people, Perkins said.
Another question arising from Tuesday's earthquake is whether it presages more damage in Haiti and elsewhere along the fault line in the Dominican Republic or Jamaica.
"It could increase the chances," said Dr. Paul Mann, senior research scientist for the Institute for Geophysics at the Jackson School of Geosciences, University of Texas, and co-author of the study presented at the 2008 earthquake conference. "The rupture in the fault line was only 50 miles long," he said. "The areas to the east and west that did not rupture are under greater loading, greater stress accumulation."
But he, too, can't predict a time — even within 30 or 50 years. For what it's worth, Dixon, the Rosenstiel geophysicist, says the fault line that caused the quake in Haiti runs too far to the south to be a danger to Cuba or Florida.
"There's no chance of an earthquake here," he says.
But he adds a chilling thought: The years-long warnings of an earthquake in Haiti of magnitude 7.0 or greater — which came true Tuesday — were almost exactly the same as the current earthquake warnings for California.
MORE FROM MCCLATCHY
Tens of thousands are feared dead in Haiti catastrophe
Public health crisis looms in Haiti
Florida groups plan to airlift Haitian orphans to U.S.
For Haitian-Americans, an agonizing wait for news
Follow continuing coverage of this story in the Miami Herald