A second brief aftershock hit Port-au-Prince last night, sending some earthquake survivors into the streets in the middle of the night.
The Associated Press reports that Haitians in the capital said the brief trembler was not as strong as several others since the magnitude-7.0 earthquake devastated the city last Tuesday.
The U.S. Geological Survey did not immediately have a measurement of the aftershock. Aftershocks can continue for months, if not years, after an earthquake strikes.
Geophysicist Susan Potter said people can feel aftershocks that register as little as magnitude-2.0, but the service has yet to detect anything weaker than a magnitude-4.5 trembler in Haiti, where detection equipment is not densely concentrated.