au-Prince, January 22, 2010, SPA -- Another aftershock has hit the Haiti capital, sending some earthquake survivors into the streets in the middle of the night, AP reported. People in Port-au-Prince said the brief trembler Thursday night was not as strong as several others since the magnitude-7.0 earthquake that devastated the city Jan. 12. Ensuing aftershocks have reached as high as magnitude-5.9. The U.S. Geological Survey did not immediately have a measurement of the aftershock. 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.