How do you fix a sink hole this big?

[Moonliner]

Originally Posted by Kevy Baby

In looking at the hole further, I am amazed by what appears to be almost perfectly straight sides to the hole. To the best of my recollection, sink-holes typically have sloped sides.

I'll have to start trolling the conspiracy web sites to see what they come up with. I can't decide between errant test of a space based energy weapon and an alien something or other.