Eight days after a 7.0 magnitude earthquake devastated Haiti, disaster returns this morning with a 6.1 magnitude aftershock. Still lying in the ruin of the first quake, Haiti is even more vulnerable than it was eight days ago. With weaker buildings already leveled and many Haitians sleeping outdoors, the greatest threat appears to be further obstacles to aid delivery, which aid groups already say is far too slow.

• The Scene On The Ground Haitian survivor Richard Morse recounts on Twitter. "Yes there was another Quake.Not as long,not as strong.It was like your mother giving you a little shake in the morning to get you out of bed. People screamed in the background..I heard what sounded like a building come crashing down. It feels like the ground is lower... The photographers went of into the city to document what may have happened..They've all started sleeping inside..don't know why." Christian missionary in Haiti Troy Livesay tweets, "Major aftershock just now...felt like a five. [...] We're all fine and and accounted for - internet is out...."

• Time for Mass Exodus Haitian musician Wyclef Jean tweets, "6.1 Earthquake again We need 2 evacuate people out side of the Capital. 2 n open field with tents through out haiti, I'm Asking 4 a Exodus buildings falling N da Capital of haiti , but n order 2 clean up da capital we need a massive Exodus. I am calling on da US Army."

• Panic Al-Jazeera's Zeina Khodr reports, "The minute the earth shook everyone started to scream, they are praying and singing religious songs. People are still very traumatized here," she said. "It's 6:30 in the morning, but people have taken to the streets with whatever belongings they have. A lot of buildings did not collapse in the quake [a week ago] but they have cracks." In the panic, many people struggled to secure food and water.

• Aid, Already Insufficient, Must Increase Voice of America warns that the second quake comes amid a still difficult situation. "Teams from all over the world have come to Haiti to provide assistance after last week's 7.0 magnitude earthquake. But efforts to distribute aid have been hampered by numerous problems, including blocked roads, bureaucratic confusion and the collapse of local authority. U.N. officials say despite the problems, progress is being made," they writes. "Survivors have been living in makeshift camps on streets littered with debris and decomposing bodies. Doctors are struggling to treat thousands of injured with limited resources. There also are increasing reports of looting and violence"

• The Difference Between The Quakes Nature Magazine explains the difference and provides "two 'shakemaps' from the USGS, showing the difference in power of these two events."

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