A 5.9 magnitude earthquake struck Haiti just after 6 a.m. ET, the U.S. Geological Survey says, and people in the already flattened city of Port-au-Prince went "running into the streets," according to the Associated Press. (3:10 p.m. ET: See our update below about a slight change in the magnitude estimate since early this morning.)
NPR's Carrie Kahn reports from Port-au-Prince that the city "just shook, it really shook, and you heard people yelling 'run, run, go!' "
She says that "structures throughout the city are so precarious ... I'm sure there was more damage throughout the city."
Haiti was devastated on Jan. 12 by a magnitude 7.0 earthquake that may have killed as many as 200,000.
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Update at 3:05 p.m. ET: The U.S. Geological Survey now says today's event was a 5.9 magnitude temblor. Its initial estimate was 6.1.
Update at 12:30 p.m. ET. More Quakes Likely. The AP writes that:
Haiti can expect more aftershocks in coming weeks, and while the usual pattern suggests they will become weaker and less frequent, another one as strong as Wednesday's jolt is certainly possible, scientists say. The battered nation has felt more than 40 aftershocks since the Jan. 12 quake, with Wednesday's temblor the strongest, with a magnitude 6.1.
These events are a sign the land is adjusting to "the new reality of the rock layers," said Bruce Pressgrave, a geophysicist with the U.S. Geological Survey.
Update at 11:15 a.m. ET. NPR's Tom Bullock now reports from Port-au-Prince that "gunshots can be heard throughout downtown — some shooting by outnumbered Haitian police trying to scare off the looters. In some cases, the looters are shooting back":
Update at 9:20 a.m. ET. More from the AP in Port-au-Prince:
The strong aftershock prompted Anold Fleurigene, 28, to grab his wife and three children and head to the city bus station. His house was destroyed in the first quake and his sister and brother killed. "I've seen the situation here, and I want to get out," he said.
Update at 8:40 a.m. ET. The AP now reports that:
U.S. soldiers and tent city refugees alike raced for open ground, and clouds of dust rose in the capital.
"It kind of felt like standing on a board on top of a ball," said U.S. Army Staff Sgt. Steven Payne. The 27-year-old from Jolo, W.Va., was preparing to hand out food to refugees in a tent camp of 25,000 quake victims when the aftershock hit.
Update at 8 a.m. ET: As we said a few moments ago, NPR's Jason Beaubien reports from the streets of Port-au-Prince that people are running into further-damaged stores to grab what they can.
"People are breaking into supermarkets. They're breaking into shoe stores. Basically grabbing whatever they can. Entire families are going into the stores," Jason says. "People are scurrying up over barbed wire, razor wire, broken chunks of concrete." Here's what it sounded like as Jason called the NPR newsroom to report on what he's seeing:
Update at 7:50 a.m. ET: Calling right now from Port-au-Prince, NPR's Jason Beaubien says he's outside a heavily damaged supermarket where a couple hundred people have gathered, many of them running in to grab what they can. Three Haitian police officers are sitting outside in a pickup truck, he says, but they are "heavily outnumbered" at the moment.
Also from Port-au-Prince, NPR's Tom Bullock says today's earthquake hit "just after first light" and is sure to have brought down some of the buildings that hadn't already fallen.
Here is Tom's audio report:
Update at 7:20 a.m. ET. NPR's Jackie Northam reports from Port-au-Prince that the walls of the already damaged building where she's staying "started shaking" and everyone ran out. But, she adds, "there's just nowhere safe here ... right now. Everywhere is vulnerable":
Update at 7:05 a.m. ET:
The AP writes that "wails of terror rose from frightened survivors of the apocalyptic quake that struck eight days ago as people as people poured out of unstable buildings. It was not immediately possible to ascertain what additional damage the new quake may have caused."
And here is audio of NPR's Kahn describing what she felt and heard: