ARTICLE - HAITI'S SHAKY FUTURE

HAITI'S SHAKY FUTURE: REDUCING EARTHQUAKE
(Our Amazing Planet)- By Brett Israel

When the Haiti earthquake struck on Jan. 12, 2010 — one year ago today — the country had only one seismometer, and it wasn't even functioning properly.

To better prepare the country for a future disaster, scientists are hard at work to try to answer the big remaining questions about the devastating magnitude-7.0 temblor. Today, a clearer picture of how it ruptured has come into focus. Yet scientists say there is still plenty of strain in the region's fault system, and there is still much to learn about how the earth is moving under Haiti.

"The goal is to come up with a better assessment of the hazard for the whole country," said Eric Calais, a geophysicist at Purdue University. "One of the key ingredients is to know where the potential sources for the earthquakes are."

Fault geometry
The Haiti quake killed more than 200,000 people and left more than 1.5 million homeless. The damage was estimated at about $8 billion, according to Munich Re, the world's largest insurer.

When the quake struck, the well-known Enriquillo fault took the blame, but scientists now know that about 85 percent of the energy from the earthquake came from a previously unknown fault, now called the Léogâne fault.

Scientists are piecing together what this fault looks like, said Gavin Hayes, a geophysicist with the USGS in Golden, Colo. Hayes worked with one of the research teams that modeled how the faults might have ruptured during the quake.

But scientists can't simply go look at the ground at the epicenter. The Léogâne fault is what's called a blind fault, meaning it doesn't rupture the surface.

"No one has ever touched the Léogâne fault, and you can't," Calais said.

Which is why scientists are conducting aftershock studies to solve this blind fault's geometry, Hayes said.

Reducing risk
Scientists aren't sure exactly how dangerous the Léogâne fault is, or whether it's part of an entire fault system that has gone undetected.

"It's quite likely that there are many faults that we don't know about, and until we look for them we won't," Calais told OurAmazingPlanet. "It's very important to put in place a project in Haiti to go after every fault capable of generating an earthquake."

Scientists think several faults slipped during Haiti's earthquake, and they are working to learn how much each one moved. Several models have been proposed, but until geologists know which is correct, they can't make the most accurate assessment of the remaining seismic hazard.

"The devil is in the details," Calais said.

Watchful eye
Before the quake struck Haiti, the country's lone seismometer was in a high school, used as a teaching aide. Now there are about 10 seismic stations that will remain in Haiti permanently, Calais said.

Geologists in Haiti, Calais included, are trying to train a generation of Haitian seismologists, of which there are currently none. It's these people that will be the future advocates of seismic risk reduction in Haiti, Calais said.

"If we want risk reduction, the effort must be made to train seismologists and earthquake engineers in Haiti," Calais said. "A seismic network is a great way to do that."