"I felt a shake, it was brief, just a few seconds," Patrice Dumont, a school teacher from the ruined town of Leogane 17 kilometres west of Port-au-Prince, said by telephone.
"I heard a sound like a grumbling, then a drumbeat, as if something wanted to burst from the belly of the earth," he added. It was not immediately clear whether the latest quake caused any damage or casualties.
The new tremor's epicenter was 30 kilometres west of the capital, at a shallow depth of 4.1 kilometres, the USGS said on its website. It struck at 4:51pm local time, or 2151 GMT.
The Haitian capital on January 12 was devastated by a 7.0 earthquake that killed more than 150,000 people, with tens of thousands still missing and hundreds of thousands made homeless.
Since the deadly quake, Haiti has suffered at least 50 aftershocks of varying intensity, and the USGS has warned that it could face more, including perhaps another catastrophic hit, over the next month.
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