NASA Jet Studies Haiti’s Fault Lines for Signs of Further Trouble
NASA is sending a radar-equipped jet to conduct flights over Haiti and the Dominican Republic to capture 3-D images that could help predict future earthquakes. An estimated 170,000 people were killed in the 7.0 earthquake that battered Haiti on January 12. Unfortunately, experts predict more quakes as the country is situated in a seismically volatile zone.
A Gulfstream III jet is now on its way to map Haiti and the Dominican Republic, the two nations that share the island of Hispaniola. The Uninhabited Aerial Vehicle Synthetic Aperture Radar, or UAVSAR, was originally on its way to Central America to study volcanoes, forests, and Mayan ruins, but on its way south it will now also study Hispaniola’s fault lines.
The principal investigator for the Hispaniola overflights, Paul Lundgren, said the aircraft will take images of the Earth’s surface and other changes associated with the Haiti earthquake. He said NASA will then analyze the 3-D results for features that could signal “aftershocks, earthquakes that might be triggered by the main earthquake farther down the fault line, and the potential for landslides” [Wired.com]. Lundgren expects the future earthquakes to be “either along adjacent sections of the Enriquillo-Plantain Garden fault that was responsible for the main earthquake, or on other faults in northern Hispaniola, such as the Septentrional fault”[Wired.com]. NASA has used this kind of radar-equipped jet in the past to examine California’s dangerous San Andreas fault.
UAVSAR flies at 41,000 feet and sends microwaves, from a pod located on the aircraft’s belly, down to the ground. It then records the returning signal. The differences in the times it takes waves to return from points on the ground to the plane gives information about the topography. By hitting the same target from different angles as the plane flies overhead, a 3-D image can be made. Very precise details about ground motion can be calculated by flying over the same area later, giving scientists information about strain buildup on a fault [Wired.com].
Haiti is located on a part of the Enriquillo-Plantain Garden fault zone–a fault that had been building up strain over the last 240 years. Scientists were expecting an earthquake in that region, but no one could predict exactly when and where. But about 100 miles to the northeast is a long segment of a similar fault, the Septentrional, that has not had a quake in 800 years. Researchers have estimated that a rupture along that segment — and again, they have no idea when one might occur — could result in a magnitude 7.5 quake that could cause severe damage in the Dominican Republic’s second-largest city, Santiago, and the surrounding Cibao Valley, together home to several million people [The New York Times] . The data collected by the UAVSAR is expected to help scientists study the potential for future earthquakes on this particular fault. The 3-D images are due to be released to the public in a few weeks.