When I first saw the pics of this thing, I thought for sure it was a hoax. My next thought was that it was the Silver Surfer preparing the planet for Galactus. Turns out, neither is correct.
Is it just me, or does this thing really look terribly unnatural?
I've actually read a few things that seem to be trying to make a point of it not being a sinkhole... if only because it's far more dangerous than a "simple" sinkhole. If I recall correctly, Guatemala City is essentially built on top of a giant ash-filled valley, which really could continue to collapse at any time.