There were no immediate reports of damage or injuries from the latest tremor.
Preliminary data from the U.S. Geological Survey show the magnitude-4.4 earthquake struck in the Caribbean Sea about 25 miles (40 kms) west of Port-au-Prince.
Even minor tremors cause panic in the Haitian capital nearly four months after a catastrophic 7.0 earthquake that the government says killed at 230,000 people.
Meanwhile, an electrical fire forced the evacuation Sunday night of 100 earthquake survivors from a smoke-filled tent hospital.
Project Medishare chief Barth Green says lightning from a rainstorm struck the ground beside the airport-side hospital's 5,000-square-foot tents.
Chief medical officer Vince Boyd says the surge caused wires to melt above an operating room. The smoldering fire spread across a pediatric tent and into another housing adult patients.
Workers carried out patients as the smoke spread. The hospital was functioning Monday.