[cstavish]

The vast majority of these detonations occurred after the US, UK and USSR signed the Limited Test Ban Treaty in 1963, which permitted only underground detonations. Ideally, underground detonations don't release radioactive material into the wider environment, but there were of course failures to contain along the way.

[batbomb]

My favorite example of an underground nuclear explosion was project gasbuggy, near where I grew up. They thought it might be useful if they could perform nuclear fracking:

http://en.wikipedia.org/wiki/Project_Gasbuggy

Where they performed the test is a very beautiful area.

Part of a larger project to actually perform nuclear terra-forming:

http://en.wikipedia.org/wiki/Operation_Plowshare

http://content.time.com/time/magazine/article/0,9171,899941,...

> Someone shouted: "We did it! We did it!" Hand shakes were exchanged all around. The U.S. had successfully set off the first nuclear explosion sponsored jointly by the Government and industry.