re: #237 Dr Lizardo
Seems like one of those slow-rolling ANFO blasts.
When I heard that characteristic WHOMP that I’d heard so many times on MythBusters (particularly when they blew up the concrete truck), I thought the same was likely, but, while it looks bad from the pics and video so far, the damage doesn’t seem to line up with that possibility, unless the bomb was botched.
If it were a proper ANFO bomb, Second Ave would look like the remains of the Murrah building.